Influence of Ni/Mo Ratio and Lanthanum Loading on Clay-Supported Ni–Mo Catalysts for In-Situ Rice Bran Pyrolysis: Optimizing Bio-Oil Yield, Deoxygenation, and Desulfurization

Influence of Ni/Mo Ratio and Lanthanum Loading on Clay-Supported Ni–Mo Catalysts for In-Situ Rice Bran Pyrolysis: Optimizing Bio-Oil Yield, Deoxygenation, and Desulfurization | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Influence of Ni/Mo Ratio and Lanthanum Loading on Clay-Supported Ni–Mo Catalysts for In-Situ Rice Bran Pyrolysis: Optimizing Bio-Oil Yield, Deoxygenation, and Desulfurization Henry O. Orugba This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7523942/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The high cost of post-pyrolysis upgrading of pyrolysis bio-oil due to its high oxygen and sulphur contents poses severe drawbacks to its use. This study investigates the influence of the Ni/Mo weight ratio and La loading on yield, deoxygenation, and desulfurization of bio-oil during in-situ catalytic pyrolysis of rice bran. The pyrolysis was performed at 450°C in a fixed bed reactor, using the catalysts synthesised via the sequential incipient wetness impregnation and calcination, with La loadings varied between 1–3 wt%, Ni between 2–10 wt%, and Mo between 2–10 wt% to identify the most effective compositions. A mesoporous catalyst with a surface area of 205.45 m²/g achieved a maximum bio-oil yield of 28.23% at a 1:1 Ni/Mo weight ratio with 1 wt% La. The low La concentration provides the balanced acidity and metal dispersion, promoting Ni hydrogenation potential and the cracking ability of Mo. A balanced Ni/Mo weight ratio also favoured sulphur removal due to the synergy of Ni promoting C–S bond cleavage and Mo facilitating sulphur adsorption. Furthermore , higher Mo content loading produced enhanced sulphur reduction due to the availability of more Mo sites for sulphur adsorption. At a 2:1 Ni/Mo weight ratio with 2 wt% La loading, La regulates acidity and enhances metal dispersion to boost Ni-driven hydrogenation, while Mo stabilises Ni active sites, achieving 89% bio-oil deoxygenation. The bio-oil exhibits diesel-range properties with higher energy value and predominant long-chain hydrocarbons. The in-situ catalytic reaction enhanced cracking and decarboxylation, which reduces the oil's oxygen and sulphur contents at the source, thus reducing the complexity and post-pyrolysis upgrading cost. Pyrolysis catalyst deoxygenation hydrogenation metal-loading Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. INTRODUCTION The search for renewable and sustainable energy sources has intensified in recent times due to the depleting fossil fuel reserves and the pollution effects associated with their usage (di Vito et al., 2021; Munoz-Arjona et al., 2025). Biomass, a renewable and highly abundant resource, is an alternative energy source due to its carbon neutrality (Perea-Moreno, 2019) and unique ability to produce varieties of fuels and other chemicals via thermochemical pathways (Patil & Vaidga, 2018). Pyrolysis is a highly preferred conversion scheme for biomass due to its ease of directly converting lignocellulosic and lipid-rich biomasses into liquid bio-oils, gases, and char (Orugba et al., 2024). The bio-oil obtained directly from the pyrolysis process is usually characterised by high oxygen content, resulting in poor thermal stability, low energy value, and high acidity (Qu et al., 2021; Xue et al., 2023; da Silva et al., 2025). In order to enhance the fuel value of bio-oil, it is usually subjected to hydrodeoxygenation, a post-pyrolysis upgrading scheme (Rueda et al., 2025; Zhang et al., 2025). Hydrodeoxygenation (HDO) is an ex-situ upgrading route, where the pyrolysis-derived bio-oil is upgraded in a separate reactor using catalysts (Munoz-Arjona et al., 2025). The process is very complex and expensive due to its high hydrogen demand. If the bio-oil oxygen content is significantly reduced during the pyrolysis step (in-situ), the hydrogen requirements in the HDO upgrade will be reduced, and the overall process economy will be improved. Apart from the deoxygenation of the resulting bio-oil, in-situ catalysis of the pyrolysis process also promotes the formation of aromatic hydrocarbons, thus improving the bio-oil stability and its energy value. The sulfided catalysts earlier developed for the HDO process are characterised by sulphur leaching and hence, prone to deactivation (Zhao & Wang, 2023). Although the second class of catalysts formulated using noble metals such as Pd, Ru, and Pt have been reported to achieve very high catalytic performance without sulphur additives (Duan, 2017; Pastor-Perez et al., 2021; Ding et al., 2021; Yan et al., 2021), the high cost of the noble metals limits their use (Kandel et al., 2014; Smirnov et al., 2016). Research is now focusing on the development of catalysts that are not just active but are also cheap, using the highly abundant transition metal systems like Ni-Co and Ni-Mo systems (Saidi et al., 2017; Ranga et al., 2018; Saidi et al., 2020; Ayala-Cortes et al., 2023). The transition metals have high hydrogen transfer capabilities, high tolerance for sulphur, nitrogen and oxygen, and high thermal stability (Han et al., 2012). The synergistic effects of these metal systems have produced high-performance catalysts that leverage the parent metals' catalytic properties. For example, in a Ni-Mo system, the Ni promotes hydrogenation and C-O bond cleavage (Ahmad et al., 2016), while the Mo enhances the catalyst's thermal stability, reduces coking tendencies, and prolongs catalyst life by adsorbing sulphur-containing compounds (Liu et al., 2021; Wang et al., 2024). Saidi et al. (2021) investigated the performance of Ni-Mo nanoparticles stabilised with ionic polymer in the deoxygenation of 4-methylanisole. They reported high catalytic activity and selectivity at high Mo content. Munoz-Arjano et al. (2025) investigated the catalytic hydrodeoxygenation of waste cooking oil into green diesel-range hydrocarbons with better quality and flow properties than commercial diesel using Mo₂C catalysts supported on carbon nanofibres. They obtained 86 mol% yield hydrocarbons in the diesel range. Wu et al. (2025) studied the hydrodeoxygenation of bio-oil products from pine nut shells using Ni-V bimetallic zeolite catalysts. Results obtained revealed decreased O/C ratio, improved LHV, and decreased water content. Boukha et al. (2022) investigated the promotional effect of La on Ni catalysts for the CO₂ methanation reaction. They reported that the addition of La enhanced catalytic activity due to improved Ni particle dispersion and their reducibility and increased the amounts of basic sites and thermal stability. Quindimil et al. (2018) investigated the influence of La addition on Ni-zeolite catalyst performance on CO₂ methanation. The addition of La produced enhanced catalytic activity due to the strong basicity of La and improved Ni dispersion. Kristensen et al. (2024) studied the promoter effect of Ce and La on Ni-Mo/δ-Al₂O₃ catalysts in the hydrodeoxygenation of vanillin and reported increased catalyst selectivity and resistance to sintering, a result attributed to the catalyst's low acidity. In acidic environments and at high temperatures, Ni-Mo catalysts are highly susceptible to coking and deactivation due to the formation of unsaturated hydrocarbons and polyaromatic compounds that deposit coke on the catalyst surface (Leyva et al., 2007). Although the use of La with strong basicity to modulate the acidity of clay-supported Ni-Mo catalysts can suppress the coking tendency and promote deoxygenation and desulfurization, optimal La loading and Ni-Mo composition that maximise product yield and improve deoxygenation and desulfurization efficiencies have not been well explored. Although several authors have investigated the use of Ni-Mo catalysts promoted with La for bio-oil upgrading, the influence of varying Ni/Mo ratios at different La loadings on these three metrics – bio-oil yield, deoxygenation, and desulfurization – has not been extensively studied, representing a critical research gap. This research investigates the influence of the Ni/Mo ratio at varying La loadings on yield, deoxygenation, and desulfurization of bio-oil during in-situ rice bran pyrolysis using clay-supported Ni-Mo catalysts. Clay, a highly abundant mineral, was chosen as the catalyst support material due to its high thermal stability and significantly high surface area. The incorporation of the La promoter into the clay matrix enhances its basicity, improves metal dispersion, and reduces sintering tendencies (Garbarino et al., 2019; Boukha et al., 2022). Understanding the influence of the Ni/Mo ratio and La loading in clay-supported Ni-Mo catalysts will enable precise tuning of their performance to maximise product yield, deoxygenation, and desulfurisation, thereby reducing material and energy demands in post-pyrolysis bio-oil upgrading and enhancing process economic viability. 2. METHODOLOGY 2.1 Material Preparation and Chemicals used Local clay samples was obtained from Oleh, a swampy community in the Niger Delta region of Nigeria. The wet clay sample was sun-dried for 3 days and further oven-dried at 110 o C for 6 hrs to reduce its moisture content. Nickel nitrate (Ni(NO 3 ) 2 .6H 2 O), lanthanum nitrate (La(NO 3 ) 2 .6H 2 O), and ammonium molybdate ((NH 4 ) 2 Mo 4 .4H2O) used as precursors for Ni, La, and Mo respectively were obtained in analytical grade and were used without further purification. Distilled water was used as solvent in preparing the different concentrations of the metal salts. Clay was chosen as the catalyst support due to its relatively high surface area and thermal stability. 2.2 Catalyst Preparation This research employed the method of incipient wetness in impregnating the metal salts into the clay support. The impregnation of the different metals was sequentially carried out using varying weights of the metal precursors to achieve the desired compositions. In order to enhance the promoting effect of La, the metal loading process on the clay began with the impregnation of La, and this was followed by nickel and then molybdenum. Adding La as the last step could reduce the catalytic activity due to the blockage of active sites (Vandevyvere et al., 2023 ). The dried clay sample was subjected to La modification using La(NO 3 ) 2 .6H 2 O, dried at 110°C for 6 hours to remove residual moisture before it was calcined at 600°C for 4 hours in order to fix La onto the clay support and promote metal-support interactions. The La-loaded clay sample was subjected to nickel impregnation and then Mo impregnation, following the same procedure outlined in La-loading. The high temperature in the calcination step helps in converting the metal salts into their corresponding oxide forms, fixing them to the support, and creating stable and active Ni and Mo catalytic phases. The active Ni and Mo phases provide the catalytic properties in the pyrolysis process. Based on the varying amounts of metals used in formulating the catalysts, 15 catalysts samples were obtained as presented in Table 1 . Table 1 Metal loadings used in the catalysts formulations Series Sample Ni loading (wt%) Mo loading (wt%) 1 wt % La A 2 10 B 4 8 C 6 6 D 8 4 E 10 2 2 wt % La A 2 10 B 4 8 C 6 6 D 8 4 E 10 2 3 wt % La A 2 10 B 4 8 C 6 6 D 8 4 E 10 2 2.3 Catalyst Characterization The prepared catalysts were characterized using Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), and the Brunauer-Emmett-Teller (BET) analysis. The FTIR analysis was employed to identify the surface functional groups present in the catalysts (Orugba & Edomwonyi, 2023), while the SEM provides the morphology and particle distribution. The specific surface area was determined using the BET model (Brunauer et al., 1938 ), and the pore size and volume were determined using the Barret-Joyner-Halenda (BJH) method (Barrett et al., 1951 ). 2.4 Pyrolysis Experiments The prepared rice bran (biomass samples) was subjected to intermediate pyrolysis in a fixed-bed reactor heated with an electric heater at a heating rate of 30°C/min, a temperature of 450°C, a residence time of 10 minutes, and a nitrogen flow rate of 1.5 L/min to maintain an inert atmosphere. For all pyrolysis experiments, 2 g of catalyst was weighed and thoroughly mixed with 20 g of biomass feedstock. The vapour from the pyrolyser was passed through a condenser where liquid components were condensed and collected as bio-oil and weighed, while the uncondensed vapours were flared. At the end of each pyrolysis experiment, the char was collected from the reactor and weighed. The mass of bio-oil and char was measured directly and converted to percentage yields as shown in Equations 1 and 2 , respectively, while the gas yield was calculated as the balance according to Eq. 3 . $$\:{Y}_{Bio-Oil}\left(\%\right)=\:\frac{\:mass\:of\:Bio-oil\:\left(g\right)}{mass\:of\:biomass\:\left(g\right)}\:\text{x}\:100\:\:\:\:\:\:$$ 1 $$\:{Y}_{Char}\left(\%\right)=\:\frac{\:mass\:of\:char\:\left(g\right)}{mass\:of\:biomass\:\left(g\right)}\:\text{x}\:100\:\:\:\:\:\:\:$$ 2 $$\:{Y}_{gas}\left(\%\right)=\:\:100\text{\%}-{Y}_{Bio-Oil}\left(\%\right)-\:{Y}_{Char}\left(\%\right)\:$$ 3 2.5 Characterization of Bio-Oil In order to obtain the catalyst sample that produced the highest degree of deoxygenated bio-oil, the bio-oil elemental analysis was carried out using a CHNS elemental analyser. The bio-oil carbon, hydrogen, nitrogen, and sulphur contents were determined directly, while oxygen content was calculated by difference. Deoxygenation efficiency was evaluated as the reduction in the bio-oil oxygen content relative to the raw biomass according to Eq. 4 . $$\:Deoxygenation\:\left(\%\right)=\frac{{O}_{biomass}-{O}_{bio-oil}}{{O}_{biomass}}$$ 4 where O biomass is the oxygen content of the biomass and O bio−oil is the bio-oil oxygen content. Further analyses of the most deoxygenated bio-oil sample were carried out. The FTIR analysis was carried out to determine the functional groups present in the bio-oil, while its composition was analysed using the gas chromatography-mass spectrometry (GC-MS) (Thermo Scientific, Austin, TX, USA). Product yields were tabulated and visualised using bar charts to evaluate the effect of La content (1–3 wt%) across the catalyst series. Statistical analysis was conducted to identify trends and correlations between catalyst composition and product distribution. 3. RESULTS AND DISCUSSIONS 3.1 Results of Catalyst Characterization The results of the different characterisation techniques employed in the characterisation of the catalysts are presented in this section. 3.1.1 FTIR Results of the Catalysts The summary table of the FTIR analysis of the catalyst sample D2, which produced the highest degree of deoxygenation, is presented in Table 2 . Table 2 FTIR summary table of the catalysts Peaks (cm − 1 ) Groups Molecular motion Type of vibration 3436.00 Alcohol O-H Stretch, H-bonded 2926.42 Alkanes C-H Stretch 2858.93 Alkanes C-H Stretch 1741.73 Aldehydes/ ketones C = O Stretch 1633.00 Alkenes C = C Stretch 1456.78 Aromatics C = C Stretch 1372.00 Alkanes C-H Bending 1239.00 Ether C-O Stretch 1163.85 Tertiary alcohol C-O Stretch 1103.81 Primary alcohol C-O Stretch 723.23 Aromatic/ aldehyde C-H/ C-Cl Out-of-plane bend/ stretch 465.57 Metal-oxide M-O Stretch As revealed in Table 2 , a broad band at 3436 cm⁻¹ indicates the presence of hydroxyl groups of alcohols or phenols, usually associated with high hydrogen bonding capacity. The peaks at 2926.42 cm⁻¹ and 2858.93 cm⁻¹ indicate C-H stretching from alkane groups. The band at 1741.73 cm⁻¹ represents C = O stretching, indicating the presence of aldehydes or ketones. The peak at 1633 cm⁻¹ indicates C = C stretching in aromatics or alkenes, while C-H bending of alkanes is depicted by 1372 cm⁻¹.. C-O stretching of esters, tertiary, and primary alcohols were respectively depicted by 1239, 1163.85, and 1103.81 cm⁻¹ peaks, which promotes catalytic activity. The 723.23 cm⁻¹ band suggests the presence of metal-oxide vibrations, likely from oxides of Ni, Mo, or La. These metal oxides formed on the catalyst's surface are essential for enhancing catalytic activity and stability. 3.1.2 Results of Catalysts BET Analysis The summary of the catalysts BET analysis is presented in Table 3 . Table 3 BET Analysis of the Catalyst Parameter/ unit Value BET surface area (m 2 /g) 205.45 Total pore volume (m 3 /g) 0.6055 BJH desorption pore volume (m 3 /g) 0.5222 Average pore diameter (BJH desorption) (nm) 3.022 BET pore diameter (adsorption) (nm) 2.754 From the summary of the catalyst BET analysis presented in Table 3 , the catalyst has a large specific surface area of 205.45 m²/g, indicating a large number of active sites. The catalyst's total pore volume of 0.655 m³/g and a BJH pore volume of 0.5222 m³/g revealed its mesoporous structure. The pore diameter obtained from BJH desorption (3.022 nm) and BET adsorption pore diameter (2.754 nm) implies the catalyst has a well-developed mesoporous structure that promotes catalytic activities. 3.1.3 Results of Catalysts SEM Analysis The SEM micrograph of the synthesized catalysts is presented in Fig. 1 . The SEM image of the catalysts shown in Fig. 1 revealed a highly porous clay matrix with irregular voids. This structural arrangement of the catalysts also supports the mesoporous structure inferred from BET analysis. The spongy morphology of the catalyst's surface may be due to the metal-oxide dispersion, which may have contributed to the creation of an open, channel-like network, a very desirable feature that promotes catalytic activity as it allows for accessibility and easy diffusion of reactant molecules throughout the catalyst matrix. 3.2 Pyrolysis Product Yield The product yield distribution obtained from the catalytic pyrolysis of the rice bran is presented in Figs. 2 – 4 . As revealed in Fig. 2 , pyrolysis product yield – oil, char, and gas – varies significantly with change in catalyst metal loading; hence, the desired product yield can be controlled via Ni/Mo ratio tuning and La weight regulation. The pyrolysis experiment carried out without a catalyst (control sample) produced the least bio-oil and highest char yields, while the catalyst series C (6 wt% Ni, 6 wt% Mo) demonstrated superior performance over other catalyst formulations in oil and char yields, especially at 1 wt% La loading, producing 28.23% oil and 47.77% char. The performance of catalyst sample C may be due to the balanced Ni/Mo ratio: Ni promotes deoxygenation and stabilises oil-phase intermediates, thus reducing secondary cracking, while Mo enhances char formation via condensation and polymerisation. As Ni outweighs Mo content (series D and E), the Ni/Mo balance was observed to shift, as oil yield falls while gas yield (Fig. 4 ) increases. This shows that high Ni content promotes excessive cracking, especially at low Mo due to low Mo stabilisation influence. Similar results were obtained by Ahmad et al. ( 2016 ) and Quindimil et al. ( 2018 ). As La content was increased to 2 wt%, more char is produced, producing the highest char of 51.8% but low oil yield. This implies that at moderate levels of La, the catalyst basicity is enhanced to promote solid-phase stability. However, further increasing La to 3 wt% produced a declined char yield. Catalysts of series B and D with low Mo content showed very high gas yields (50.46 and 47.4%, respectively) and low oil and char yields, revealing the dual nature of La. Moderate La promotes polymerisation and char-forming tendency; higher loadings shift the catalyst's acidity to favour cracking (Escobar et al., 2023 ), producing more gases. Thus, a balanced Ni/Mo at moderate La loadings (1–2 wt%) is the best catalyst formulation for maximising oil yield. 3.3 Degree of Deoxygenation (DoD) of Bio-oil Since low oxygen content is a key parameter in producing quality bio-oil, the oxygen-removal tendency of any catalyst is very important in formulating a catalyst for biomass pyrolysis. The degree of deoxygenation (DoD) of the bio-oil obtained using different catalyst formulations with varied Ni/Mo/La metal loadings is presented in Fig. 5 . As depicted in Fig. 5 , low La loading of 1 wt% in series C (6 wt% Ni, 6 wt% Mo) and D (8 wt% Ni, 4 wt% Mo) produced the highest degree of deoxygenation (DoD) values of 69.95% and 74.46%, respectively, revealing Ni's role in promoting hydrodeoxygenation. For series C, the Ni/Mo ratio provides optimal conditions for hydrodeoxygenation due to the synergistic effect of Ni/Mo: Ni promoting deoxygenation and Mo promoting the stability of Ni particles. At 1 wt% La loading, catalysts of series A (2 wt% Ni, 10 wt% Mo) and B (4 wt% Ni, 8 wt% Mo) produced lower bio-oil DoD values of 38.3% and 36.11%, respectively. The high Mo content and low Ni content limit the number of available active sites for hydrogenation, resulting in incomplete deoxygenation. This implies that Mo alone is less effective for HDO and must require Ni activation to produce sufficient hydrogenation. At moderate La loading (2 wt%), the bio-oil DoD was significantly increased, especially for catalyst D2 (8 wt% Ni, 4 wt% Mo, 2 wt% La), producing the highest DoD of 89%. This high performance of catalyst D2 suggests that La is a good structural promoter, improving metal dispersion, reducing sintering tendency, and enhancing basicity on the catalyst surface (Garbarino et al., 2019 ; Boukha et al., 2022 ), which is necessary for adsorption and conversion of oxygen groups. Catalyst C remaining stable at 70% further confirms the robustness of the balanced Ni/Mo ratio even at various La loadings. However, the low DoD demonstrated by catalyst B (24.57%) revealed that the promoting effect of La alone cannot compensate for a poorly balanced Ni/Mo ratio. The moderate increase in DoD for catalyst series A (49.16%) and E (55.91%) also confirms that La improves the catalytic activity at sufficiently high Ni. At 3 wt% La, catalyst sample C dominates, producing 81%, while a decline to 71.1% and 60.65% was observed for D and E, respectively. This may be due to either the very high Ni loading, which leads to deactivation due to increased sintering and coke-forming tendencies (Ahmad et al., 2016 ; Quindimil et al., 2018 ), or the high La loading that reduces acidity by covering acidic sites with the basic La₂O₃ (Escobar et al., 2023 ). This result revealed that Ni is the primary metal responsible for deoxygenation (Nuhma et al., 2022 ; Kristensen et al., 2024 ), while Mo plays the supporting role of maintaining catalyst structure and regulating acidity, and La in moderate loading improves metal dispersion and supports HDO activity (Garbarino et al., 2019 ; Escobar et al., 2023 ). 3.4 Degree of Desulfurization (DDS) of Bio-oil The degree of desulfurization of the bio-oil from the pyrolysis process using the various catalyst samples is presented in Fig. 6 . As depicted in Fig. 6 , sulphur removal is strongly influenced by Ni/Mo loading at different La weights. At 1 wt% La, the highest sulphur removal of 78.38% was obtained using catalyst sample C (6 wt% Ni, 6 wt% Mo), and this is closely followed by catalyst samples B and D, while catalyst sample E with the least content of Mo (2 wt%) and highest Ni (10 wt%) produced the lowest degree of sulphur removal (35.14%). This clearly revealed that a balanced Ni/Mo weight ratio favours sulphur removal, as Ni promotes hydrodeoxygenation and C-S bond cleavage, while Mo supports the adsorption of sulphur and promotes Ni site stabilisation, as reported by several authors (Liu et al., 2021 ; Zhu et al., 2023 ; Wang et al., 2024 ). On increasing La to 2 wt%, a significant boost in sulphur removal (84%) was recorded using catalyst sample A with low Ni (2 wt%) and high Mo (10 wt%), while samples C and D also performed very well, reaching values above 81%. At moderately high La loading, increasing the Mo loading produced a significant reduction in sulphur content since the La dispersion is improved (Garbarino et al., 2019 ; Boukha et al., 2022 ), thus enhancing its sulphur adsorbing power (Wang et al., 2024 ). Even the performance of catalyst sample E that was very poor at 1 wt% La was highly increased to 67.5% at 2 wt% La, which further confirms that a relatively high La content in the catalyst could offset low Mo content. As La was increased to 3 wt%, the performances of the catalyst samples were also enhanced, with sample D producing 83.7% sulphur removal and even E still increasing to 78.33%. Thus, it could be inferred that a very high La content in the catalyst sample may offset the low Mo loading and promote desulfurization. However, the slight decline in catalysts sample C to 70.27% may be due to excess La covering active sites. 3.4 Bio-Oil Characterization 3.4.1 Physichochemical Properties of Bio-Oil A comparative analysis of fuel properties of the bio-oil obtained from uncatalyzed pyrolysis (control) and the catalyzed pyrolysis using the catalysts sample D2- sample that produced the highest degree of deoxygenation are presented in Table 4 . Table 4 Physicochemical properties of bio-oils from the catalyzed and uncatalyzed pyrolysis Property/ Units Control Catalyzed oil Acid Value (mg KOH/g) 14.18 6.76 Ash Content (%) 0.02 0.01 Calorific Value (MJ/kg) 16 32 Density (g/cc) 1.06 0.85 Flash Point ( o C) 115 120 Moisture content (wt%) 25 15 pH 3.69 5.31 Pour Point ( o C) -11 -7 Viscosity (cSt) 2.19 1.21 The bio-oil obtained from the catalysed pyrolysis has superior fuel properties compared with the bio-oil from the uncatalysed pyrolysis. The acid value of the bio-oil from the catalysed pyrolysis, with a value of 6.76, is significantly lower than the value of 14.18 obtained for the uncatalysed process. A lower acidity value enhances bio-oil stability and reduces corrosivity. The lower ash content (0.01%), higher energy value (32 MJ/kg), and the relatively low density (0.85 g/cc) of the bio-oil from the catalysed process bring its quality closer to the range of diesel fuels (Suhaimia et al., 2018 ). Furthermore, the bio-oil from the catalysed pyrolysis has lower moisture content (15%) and a higher flash point (120°C), indicating its better fuel qualities. 3.4.2 FTIR Analysis of Bio-Oil The FTIR peaks representing the different functional groups present in the bio-oil obtained from the catalysed pyrolysis are presented in Table 5 . Table 5 FTIR summary table of the bio-oil Peaks (cm − 1 ) Groups Molecular motion Type of vibration 4336.51 O–H (water, alcohol) O–H Stretch, H-bonded 4196.00 O–H (alcohol/phenol) O–H Stretch 3781.00 Free O–H O–H Stretch 3749.17 Free O–H O–H Stretch 3409.00 Alcohol/Phenol O–H Stretch, H-bonded 3344.00 Alcohol/Phenol O–H Stretch, H-bonded 2927.00 Alkanes C–H Stretch 2861.71 Alkanes C–H Stretch 2067.13 Alkyne/C ≡ C C ≡ C Stretch 2038.00 Alkyne/C ≡ C C ≡ C Stretch 1725.62 Aldehydes/Ketones/Carboxylic acids C = O Stretch 1450.95 Alkanes CH₂/CH₃ Bending 1239.00 Esters/Ethers C–O Stretch 1174.22 Primary alcohol C–O Stretch 951.63 Alkenes =C–H Out-of-plane bend 719.34 Aromatic/alkane C–H (CH₂ rocking) Bending 413.99 Metal–oxide residue M–O Stretch The bio-oil FTIR summary table presented in Table 5 revealed a complex chemical composition with different functional groups. The broad bands between 4336 and 3344 cm⁻¹ represent the OH vibrations associated with alcohols and phenols (Dai et al., 2023 ). Peaks at 2927 and 2861 cm⁻¹ depicting CH groups suggest the presence of alkanes, which enhances the fuel properties of the bio-oil. Peaks at 2067 and 2038 cm⁻¹ indicate the occurrence of C ≡ C groups, while the peak at 1726 cm⁻¹ indicates C = O stretching vibrations of ketones, aldehydes, or carboxylic acids (Saito et al., 2022 ). Other prominent groups detected in the bio-oil include C-O stretching of esters, ethers, and primary alcohols represented by 1239 and 1174 cm⁻¹.. Despite the high degree of deoxygenation recorded by the catalysts, the bio-oil needs upgrading to further reduce the quantity of oxygenated compounds and hence, raise its fuel properties. 3.4.3 Result of the Bio-Oil GC-MS Analysis The GC-MS analysis of the bio-oil obtained from the catalyzed pyrolysis is presented in Table 6 . Table 6 GC-MS Analysis of the bio-oil S/No. RT (mins) Compound Name Area % 1 5.60 Octane 1.20 2 7.70 Decanoic acid 1.60 3 12.35 1-undecene 3.60 4 13.20 1-dodecene 1.65 5 18.40 Dodecene 8.60 6 19.82 1, 12-tridecadiene 1.20 7 23.70 3-tetradecene 10.50 8 25.60 Tridecane 16.30 9 34.82 3-tetradecane 10.20 10 29.42 3-tetradecene 2.65 11 38.65 Hexadecane 5.20 12 40.20 Cyclohexane, 1,5-diisopropyl-2,3-dimethyl 1.22 13 42.60 1-hexadecene 3.60 14 45.40 Methyl-hexadecadienoate 1.10 15 45.90 Isopropylmyristate 3.65 16 46.40 3-octadecanone 0.70 17 53.50 1-octadecanethiol 1.15 18 55.22 Methyllinolelaidate 4.60 19 65.35 Methylelaidate 5.30 20 62.22 Methyl-octadecenoate 0.07 21 57.20 1-docosene 1.12 The GC-MS result of the bio-oil presented in Table 6 represents a complex system of 21 compounds, predominantly long-chain hydrocarbons. The major compounds revealed by the GC-MS analysis include tridecane, tetradecane, tetradecene, and hexadecane. These diesel-range paraffins and olefins (Knobloch et al., 2021 ) might have contributed significantly to the high calorific value of the bio-oil. However, the bio-oil still contains some amount of alkenes and dienes, indicating some level of unsaturation. 4. CONCLUSION A study to investigate the performance of La-promoted Ni-Mo/clay catalysts to obtain low-oxygen and low-sulphur bio-oil in the in-situ pyrolysis of rice bran has been carried out. The optimised mesoporous catalysts with a surface area of 205.45 m²/g have well-developed active sites for high catalytic activities and obtained an optimal bio-oil yield of 28.23% at a balanced 1:1 Ni/Mo ratio and at 1 wt% La loading. At this configuration, the synergistic effect of the hydrogenation ability of Ni and the cracking tendency of Mo is optimised. Slightly increasing La loading to 2 wt% promotes sulphur removal due to the improved metal dispersion, ensuring optimal performance of Mo in active site stability and promoting C-S bond cleavage activities of Ni. Optimum deoxygenation was achieved at a higher Ni/Mo ratio (2:1) and moderate La loading (2 wt%). The relatively high La concentration improved metal dispersion, reducing the sintering tendency and enhancing basicity, which favours the ability of Ni to adsorb and convert oxygen. These well-tailored Ni-Mo/La-formulated catalysts can significantly reduce oxygen and sulphur contents of bio-oil in the pyrolysis stage and hence reduce the complexity and cost of post-pyrolysis upgrades. Abbreviations HDO hydrodeoxygenation Y Bio oil-bio-oil yield Y Char Biochar yield Y gas Gas yield O biomass biomass oxygen content O oil oil oxygen content DoD degree of deoxygenation DDS degree of desulfurization Declarations Ethics and Consent to Participate This study did not involve human participants, animals, or any other subjects requiring ethical approval or consent. Consent for Publication As the sole author, I consent to the publication of this manuscript and its associated data in Catalysis Letters. No human participants or other entities requiring consent were involved in this study. Competing Interest The author declares no competing interests, financial or non-financial, that could influence the research or its outcomes Author Contribution As the sole author, Henry O. Orugba conceived the study, designed the experiments, prepared and characterized the catalysts, conducted the pyrolysis experiments, analyzed the data, interpreted the results, and wrote the manuscript. Funding Declaration The author did not receive any funding for this research work. Data Availability Statement The data that support the findings of this study are available upon reasonable request. Please contact the corresponding author Dr H.O Orugba at [email protected] to inquire about access to the data. Acknowledgments I sincerely acknowledge my 2024/2025 final-year students in the Department of Chemical Engineering under my supervision for their technical assistance in catalyst synthesis and their helpful discussions. References Ahmad M., Farhana R., Raman A.A.A., Bhargava S.K. (2016). Synthesis and activity evaluation of heterometallic nano oxides integrated ZSM-5 catalysts for palm oil cracking to produce biogasoline. Energy Conversion and Management, 119, 352–360. Ayala-Cort´es A., Torres D., Frecha E., Arcelus-Arrillaga P., Villafan-Vidales H.I.,´ Longoria A., Pinilla J.L., Suelves I. (2023). Upgrading of biomass-derived solar hydrothermal bio-oils through catalytic hydrodeoxygenation in supercritical ethanol, Journal of Environmental Chemical Engineering, 11 (6), 111395, https://doi.org/10.1016/j. jece.2023.111395. Barrett E. P., Joyner L. G., Halenda P. P. (1951). The Determination of Pore Volume and Area Distributions in Porous. I. Computations from Nitrogen Isotherms. Journal of American Chemical Society, 73, 373−380. Boukha Z., Bermejo-Lopez A., Pereda-Ayo B., Gonzalez-Marcos J.A., Gonzalez-Velasco J.R. (2022). Study on the promotional effect of lanthana addition on the performance of hydroxyapatite-supported Ni catalysts for the CO 2 Methanation Reaction. Applied Catalysis B-Environmental, 314, 121500 Brunauer S., Emmett P. H., Teller E. (1938). Adsorption of Gases in Multimolecular Layers. Journal of American Chemical Society, 60, 309−319. da Silva T.L., Dutra F., Marques S., Gomes M., Costa P., Paradela F., Ferreira F.C., Faria N.T., Mugica P., Pinheiro H.M. et al. (2025). Production of sustainable aviation fuel precursors using the oleaginous yeast Rhodotorula toruloides PYCC 5615 cultivated on eucalyptus bark hydrolysate. Biomass Bioenergy, 197, 107790. Dai, F., Zhuang, Q., Huang, G., Deng, H., & Zhang, X. (2023). Infrared Spectrum Characteristics and Quantification of OH Groups in Coal. ACS Omega, 8, 17064 - 17076. https://doi.org/10.1021/acsomega.3c01336. di Vito Nolfi G., Gallucci K., Rossi L. (2021). Green Diesel Production by Catalytic Hydrodeoxygenation of Vegetables Oils. International Journal of Environmental Research and Public Health, 18, 13041 Ding W., Li H., Zong R., Jiang J., Tang X. (2021). Controlled Hydrodeoxygenation of Biobased Ketones and Aldehydes over an Alloyed Pd–Zr Catalyst under Mild Conditions. ACS Sustainable Chemistry and Engineering, 9, 3498–3508. Duan, Y. (2017). Synthesis of Renewable Diesel Range Alkanes by Hydrodeoxygenation of Palmitic Acid over 5% Ni/CNTs under Mild Conditions. Catalysts 7 (12), 81. doi:10.3390/catal7030081 Escobar J., Barrera M. C., Santes V. F., Fouconnier B. (2023). Guaiacol HDO on La-modified Pt/Al2O3: Influence of rare-earth loading. Canadian Journal of Chemical Engineering, 101, 5772−5784. Garbarino G., Wang C., Cavattoni T., Finocchio E., Riani P., Flytzani- Stephanopoulos M., Busca G. (2019). A study of Ni/La-Al2O3 catalysts: a competitive system for CO2 methanation. Applied Catalysis B-Environmental, 248, 286–297 Han, J., Duan, J., Chen, P., Lou, H., Zheng, X., and Hong, H. (2012). CarbonSupported Molybdenum Carbide Catalysts for the Conversion of Vegetable Oils. ChemSusChem 5 (4), 727–733. doi:10.1002/cssc.201100476 Kandel, K., Anderegg, J. W., Nelson, N. C., Chaudhary, U., and Slowing, I. I. (2014). Supported Iron Nanoparticles for the Hydrodeoxygenation of Microalgal Oil to Green Diesel. Journal of Catalysis, 314, 142–148. doi:10.1016/j.jcat.2014.04.009 Knobloch, M., Schinkel, L., Schilling, I., Kohler, H., Lienemann, P., Bleiner, D., & Heeb, N. (2021). Transformation of short-chain chlorinated paraffins by the bacterial haloalkane dehalogenase LinB - Formation of mono- and di-hydroxylated metabolites. Chemosphere, 262, 128288 . https://doi.org/10.1016/J.CHEMOSPHERE.2020.128288. Kristensen T.A., Hulterberg C.P., Wallenberg R.L., Abdelaziz O.Y., Blomberg S. (2024). Promoting Effect of Ce and La on Ni−Mo/δ-Al2O3 Catalysts in the Hydrodeoxygenation of Vanillin. Energy and Fuels, 38(11), 9827-9835. https://doi.org/10.1021/acs.energyfuels.4c00898 Leyva, C., Rana, M. S., Trejo, F., and Ancheyta, J. (2007). On the Use of Acid-BaseSupported Catalysts for Hydroprocessing of Heavy Petroleum. Industrial and Engineering Chemistry Research, 46 (23), 7448–7466. doi:10.1021/ie070128q Liu, X., Yan, J., Mao, J., He, D., Yang, S., Mei, Y., & Luo, Y. (2021). Inhibitor, co-catalyst, or intermetallic promoter? Probing the sulfur-tolerance of MoOx surface decoration on Ni/SiO2 during methane dry reforming. Applied Surface Science, 548, 149231. https://doi.org/10.1016/J.APSUSC.2021.149231. Munoz-Arjona A., Ayala-Cortes A., Di Stasi C., Torres D., Pinilla J.L., Suelves I.C. (2023). Catalytic hydrodeoxygenation of waste cooking oil into green diesel range hydrocarbons: From batch to continuous processing. Chemical Engineering Journal 503, 158303. https://doi.org/10.1016/j.cej.2024.158303 Nuhma, M. J., Alias, H., Tahir, M., & Jazie, A. A. (2022). Catalytic Deoxygenation of Hydrolyzed Oil of Chlorella Vulgaris Microalgae over Lanthanum-Embedded HZSM-5 Zeolite Catalyst to Produce Bio-Fuels. Molecules , 27 (19), 6527. https://doi.org/10.3390/molecules27196527 Orugba H. O., Osagie C., Owamah H. I., Edomwonyi-Otu L. C. (2024). Sustainable Faecal Sludge Management in Internally Displaced Persons (IDPs) Settlements in Tropical Climate: A Review. Nigerian Journal of Technology, 43(1), 172 – 188; https://doi.org/10.4314/njt.v43i1. 19 Orugba H.O., Edomwonyi-Otu L.C. (2023). Improving the Activity and Stability of Turtle Shell-derived Catalyst in Alcoholysis of Degraded Vegetable Oil: An Experimental Design Approach. Journal of King Saud University-Engineering Science, 35(4), 975-303. doi: 10.1016/j.jksues.2021.05.001. Pastor-Pérez L., Jin W., Villora-Picó J.J., Wang Q., Pastor-Blas M.M., Sepúlveda-Escribano A., Reina T.R. (2021). H 2 -free demethoxylation of guaiacol in subcritical water using Pt supported on N-doped carbon catalysts: A cost-effective strategy for biomass upgrading. Journal of Energy Chemistry, 58, 377–385 Patil, S. J., and Vaidya, P. D. (2018). On the Production of Bio-Hydrogenated Diesel over Hydrotalcite-like Supported Palladium and Ruthenium Catalysts. Fuel Processing Technology, 169, 142–149. doi:10.1016/j.fuproc.2017.09.026 Perea-Moreno, M.-A.; Samer ón-Manzano, E.; Perea-Moreno, A.-J. Biomass as Renewable Energy: Worldwide Research Trends. Sustainability 2019, 11, 863. Qu L., Jiang X., Zhang Z., Zhang X.-G., Song G.-Y., Wang H.-L., Yuan Y.-P., Chang Y. L. (2021). A review of hydrodeoxygenation of bio-oil: Model compounds, catalysts, and equipment. Green Chemistry, 23, 9348–9376. Quindimil A., De-La-Torre U., Pereda-Ayo B., Gonz´alez-Marcos J.A., Gonz´alez- Velasco J.R. (2018). Ni catalysts with La as promoter supported over Y- and BETA- zeolites for CO2 methanation, Applied Catalysis B-Environmental, 238, 393–403. Ranga C., Lødeng R., Alexiadis V.I., Rajkhowa T., Bjørkan H., Chytil S., Svenum I.H., Walmsley J., Detavernier C., Poelman H., Voort P.V.D., Thybaut J.W. (2018). Effect of composition and preparation of supported MoO 3 catalysts for anisole hydrodeoxygenation. Chemical Engineering Journal, 335,120-132. Rueda A.C., Granados-Reyes J., Delaunay J., Mora-Masi à P., Cesteros Y. (2025). Tuning the acid base properties of layered double hydroxides for the selective obtention of cyclohexane and cyclohexanol in the hydrodeoxygenation of guaiacol. Chemical Engineering Journal, 512, 162226. Saidi M, Baharan S.N.R. (2020). Kinetic modeling and experimental investigation of hydro-catalytic upgrading of anisole as a model compound of bio-oils derived from fast pyrolysis of lignin over Co/ g-Al 2 O 3 . Chemistry, 5, 2379-2387. Saidi M., Rahzani B., Rahimpour M.R. (2017). Characterization and catalytic properties of molybdenum supported on nano gamma Al 2 O 3 for upgrading of anisole model compound. Chemical Engineering Journal,319,143-154. Saidi M., Safaripour M. (2021). Ni–Mo nanoparticles stabilized by ether functionalized ionic polymer: A novel and efficient catalyst for hydrodeoxygenation of 4-methylanisole as a representative of lignin-derived pyrolysis bio-oils. International Journal of Hydrogen Energy, 46(2), 2191-2203. Saito, K., Xu, T., & Ishikita, H. (2022). Correlation between C=O Stretching Vibrational Frequency and pKa Shift of Carboxylic Acids. The Journal of Physical Chemistry B, 126, 4999 - 5006. https://doi.org/10.1021/acs.jpcb.2c02193. Smirnov, A. A., Khromova, S. A., Ermakov, D. Y., Bulavchenko, O. A., Saraev, A. A., Aleksandrov, P. V., et al. (2016). The Composition of Ni-Mo Phases Obtained by NiMoOx-SiO2 Reduction and Their Catalytic Properties in Anisole Hydrogenation. Applied Catalysis A: General 514, 224–234. doi:10.1016/j. apcata.2016.01.025 Suhaimia, H., Adama, A., Mrwana, A., Abdullaha, Z., Fahmi, M. O., Kamaruzzamana, M., & Hagosb, F. (2018). Analysis of combustion characteristics, engine performances and emissions of long-chain alcohol-diesel fuel blends. Fuel, 220, 682-691. https://doi.org/10.1016/J.FUEL.2018.02.019. Vandevyvere T., Sabbe M.K., Bouriakova A., Saravanamurugan S., Thybaut J.W., Lauwaert J. (2023). Impact of the incipient wetness impregnation sequence during the preparation of La or Ce promoted NiCu-Al 2 O 3 on low-temperature hydrodeoxygenation. Catalysis Communications, 181, 106734. Wang, Y., Su, Z., Duan, M., Fan, H., Ju, S., & Yang, C. (2024). Insights into the coupling of H2S adsorption and subsequent C4H4S hydrogenation over Ni–Mo composite adsorbents. Chemical Engineering Science. https://doi.org/10.1016/j.ces.2024.120707. Wu Y., Xu X., Fan X., Sun Y., Tu R., Jiang E., Xu Q., Xu C.C. (2025). Catalytic Hydrodeoxygenation of Pyrolysis Volatiles from Pine Nut Shell over Ni-V Bimetallic Catalysts Supported on Zeolites. Catalysts, 15, 498. https://doi.org/10.3390/ catal15050498 Xue X., Liu J., Xia D., Liang J. (2023). Hydrocarbon-rich bio-oil production from the coupling formaldehyde-pretreatment and catalytic pyrolysis of poplar sawdust. Biomass Bioenergy, 173, 106807. Yan P., Mensah J., Drewery M., Kennedy E., Maschmeyer T., Stockenhuber M. (2021). Role of metal support during ru-catalysed hydrodeoxygenation of biocrude oil. Applied Catalysis B Environmental, 281, 119470. Zhang W., Wang F., Feng J., Pan H. (2025). Effiient hydrodeoxygenation of guaiacol to cyclohexanol over Ni–Co bimetallic nanoparticles supported on Al2O3–TiOx. Biomass Bioenergy, 197,107841. Zhao S., Wang K. (2023). Regulation of the Reaction Route in Hydrogenation of Renewable Palm Oil Using NiMo Bimetallic Catalyst, Energy Fuel 37 (23),18899–18910, https://doi.org/10.1021/acs.energyfuels.3c02598. Zhu, H., Dong, S., Xiong, J., Wan, P., Jin, X., Lu, S., Zhang, Y., & Fan, H. (2023). MOF derived cobalt-nickel bimetallic phosphide (CoNiP) modified separator to enhance the polysulfide adsorption-catalysis for superior lithium-sulfur batteries.. Journal of colloid and interface science, 641, 942-949 . https://doi.org/10.1016/j.jcis.2023.03.083. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7523942","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":515168772,"identity":"73612feb-f91c-4d94-8946-0da1635eb1ac","order_by":0,"name":"Henry O. Orugba","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5UlEQVRIiWNgGAWjYJACZgaGAyCa8QGQ4OEjRQuzAUgLGyla2CTAJCHl/NJnjF8X1NyRM5c+Y1b5NcdOho2B+eGjG3i0SPblmFnPOPbM2BLIuC27LRnoMDZj4xw8WgzO8JgZ87AdTtwAZNyW3MYM1MLDJk1Yy7/D9SAtxZLb6onSYvyYt+1wAkgv48dthwlrkexhK2Oe2XfYcMMZtmJpxm3HediYCfiFn4d58+eCb4flDc4wb/z4c1u1PT9788PH+LQwwKKDgYHDgJkHRDPjVw5W8gFCsz9g/EFY9SgYBaNgFIxAAABGCUPTMEL6QAAAAABJRU5ErkJggg==","orcid":"","institution":"Delta State University","correspondingAuthor":true,"prefix":"","firstName":"Henry","middleName":"O.","lastName":"Orugba","suffix":""}],"badges":[],"createdAt":"2025-09-03 07:23:40","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7523942/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7523942/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":91629535,"identity":"a985cc8c-b949-4c7f-9b71-fe3089bfed40","added_by":"auto","created_at":"2025-09-18 12:48:16","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":193566,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSEM image of catalysts sample\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe figure illustrates the SEM micrograph of the synthesized catalysts. The figure revealed a highly porous clay matrix with irregular voids.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7523942/v1/14b5209fe81bd49f3ff32a69.png"},{"id":91630982,"identity":"17a9d8b0-5857-4c75-be21-1abaf49dc243","added_by":"auto","created_at":"2025-09-18 13:04:16","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":22630,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBio-oil yield at different La weight percentages in Ni-Mo Catalysts\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe figure presents bio-oil yield in the pyrolysis process using the different catalysts synthesized with varying Ni-Mo ratios at different La loadings. It helps to illustrate how the concentration of metals in the catalyst affect bio-oil yield.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7523942/v1/0ce47912bce120853a59150e.png"},{"id":91630506,"identity":"92e4f664-013e-4104-8a28-10dba364d55c","added_by":"auto","created_at":"2025-09-18 12:56:16","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":21886,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eChar yield at different La weight percentages in Ni-Mo Catalysts\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe figure presents bio-char yield in the pyrolysis process using the different catalysts synthesized with varying Ni-Mo ratios at different La loadings.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7523942/v1/b89374bb6128a1d937a52609.png"},{"id":91629540,"identity":"d293705c-7384-48c7-ae79-301d943658b7","added_by":"auto","created_at":"2025-09-18 12:48:16","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":22983,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eGas yield at different La weight percentages in Ni-Mo Catalysts\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe figure presents gas yield in the pyrolysis process using the different catalysts synthesized with varying Ni-Mo ratios at different La loadings.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7523942/v1/2de5f729727a93a4099064b8.png"},{"id":91629539,"identity":"111cb9b4-d444-4c12-92b5-b0a67c90856a","added_by":"auto","created_at":"2025-09-18 12:48:16","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":24115,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBio-oil degree of deoxygenation at different La weight percentages in Ni-Mo Catalysts\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe figure presents the degree of deoxygenation (DoD) of the bio-oil obtained using different catalyst formulations with varied Ni/Mo/La metal loadings.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7523942/v1/2c42d2f297be0eac5d099adc.png"},{"id":91630508,"identity":"0f411a36-3ccb-413e-992e-6ef49cb46ede","added_by":"auto","created_at":"2025-09-18 12:56:16","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":24718,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBio-oil degree of desulfurization at different La weight percentages in Ni-Mo Catalysts\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe figure presents the degree of desulfurization of the bio-oil from the pyrolysis process using the various catalyst samples.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7523942/v1/57e89b10bf75e5410c292b6d.png"},{"id":101297040,"identity":"af55cf06-8f14-48ed-bd8d-28774d6e07df","added_by":"auto","created_at":"2026-01-28 09:24:42","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1472955,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7523942/v1/ea419a33-5f69-4fb8-8f4e-0ba7977e11ad.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Influence of Ni/Mo Ratio and Lanthanum Loading on Clay-Supported Ni–Mo Catalysts for In-Situ Rice Bran Pyrolysis: Optimizing Bio-Oil Yield, Deoxygenation, and Desulfurization","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003eThe search for renewable and sustainable energy sources has intensified in recent times due to the depleting fossil fuel reserves and the pollution effects associated with their usage (di Vito et al., 2021; Munoz-Arjona et al., 2025). Biomass, a renewable and highly abundant resource, is an alternative energy source due to its carbon neutrality (Perea-Moreno, 2019) and unique ability to produce varieties of fuels and other chemicals via thermochemical pathways (Patil \u0026amp; Vaidga, 2018). Pyrolysis is a highly preferred conversion scheme for biomass due to its ease of directly converting lignocellulosic and lipid-rich biomasses into liquid bio-oils, gases, and char (Orugba et al., 2024). The bio-oil obtained directly from the pyrolysis process is usually characterised by high oxygen content, resulting in poor thermal stability, low energy value, and high acidity (Qu et al., 2021; Xue et al., 2023; da Silva et al., 2025). In order to enhance the fuel value of bio-oil, it is usually subjected to hydrodeoxygenation, a post-pyrolysis upgrading scheme (Rueda et al., 2025; Zhang et al., 2025).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eHydrodeoxygenation (HDO) is an ex-situ upgrading route, where the pyrolysis-derived bio-oil is upgraded in a separate reactor using catalysts (Munoz-Arjona et al., 2025). The process is very complex and expensive due to its high hydrogen demand. If the bio-oil oxygen content is significantly reduced during the pyrolysis step (in-situ), the hydrogen requirements in the HDO upgrade will be reduced, and the overall process economy will be improved. Apart from the deoxygenation of the resulting bio-oil, in-situ catalysis of the pyrolysis process also promotes the formation of aromatic hydrocarbons, thus improving the bio-oil stability and its energy value.\u003c/p\u003e\n\u003cp\u003eThe sulfided catalysts earlier developed for the HDO process are characterised by sulphur leaching and hence, prone to deactivation (Zhao \u0026amp; Wang, 2023). Although the second class of catalysts formulated using noble metals such as Pd, Ru, and Pt have been reported to achieve very high catalytic performance without sulphur additives (Duan, 2017; Pastor-Perez et al., 2021; Ding et al., 2021; Yan et al., 2021), the high cost of the noble metals limits their use (Kandel et al., 2014; Smirnov et al., 2016). Research is now focusing on the development of catalysts that are not just active but are also cheap, using the highly abundant transition metal systems like Ni-Co and Ni-Mo systems (Saidi et al., 2017; Ranga et al., 2018; Saidi et al., 2020; Ayala-Cortes et al., 2023). The transition metals have high hydrogen transfer capabilities, high tolerance for sulphur, nitrogen and oxygen, and high thermal stability (Han et al., 2012). The synergistic effects of these metal systems have produced high-performance catalysts that leverage the parent metals' catalytic properties. For example, in a Ni-Mo system, the Ni promotes hydrogenation and C-O bond cleavage (Ahmad et al., 2016), while the Mo enhances the catalyst's thermal stability, reduces coking tendencies, and prolongs catalyst life by adsorbing sulphur-containing compounds (Liu et al., 2021; Wang et al., 2024).\u003c/p\u003e\n\u003cp\u003eSaidi et al. (2021) investigated the performance of Ni-Mo nanoparticles stabilised with ionic polymer in the deoxygenation of 4-methylanisole. They reported high catalytic activity and selectivity at high Mo content. Munoz-Arjano et al. (2025) investigated the catalytic hydrodeoxygenation of waste cooking oil into green diesel-range hydrocarbons with better quality and flow properties than commercial diesel using Mo₂C catalysts supported on carbon nanofibres. They obtained 86 mol% yield hydrocarbons in the diesel range. Wu et al. (2025) studied the hydrodeoxygenation of bio-oil products from pine nut shells using Ni-V bimetallic zeolite catalysts. Results obtained revealed decreased O/C ratio, improved LHV, and decreased water content. Boukha et al. (2022) investigated the promotional effect of La on Ni catalysts for the CO₂ methanation reaction. They reported that the addition of La enhanced catalytic activity due to improved Ni particle dispersion and their reducibility and increased the amounts of basic sites and thermal stability. Quindimil et al. (2018) investigated the influence of La addition on Ni-zeolite catalyst performance on CO₂ methanation. The addition of La produced enhanced catalytic activity due to the strong basicity of La and improved Ni dispersion. Kristensen et al. (2024) studied the promoter effect of Ce and La on Ni-Mo/δ-Al₂O₃ catalysts in the hydrodeoxygenation of vanillin and reported increased catalyst selectivity and resistance to sintering, a result attributed to the catalyst's low acidity.\u003c/p\u003e\n\u003cp\u003eIn acidic environments and at high temperatures, Ni-Mo catalysts are highly susceptible to coking and deactivation due to the formation of unsaturated hydrocarbons and polyaromatic compounds that deposit coke on the catalyst surface (Leyva et al., 2007). Although the use of La with strong basicity to modulate the acidity of clay-supported Ni-Mo catalysts can suppress the coking tendency and promote deoxygenation and desulfurization, optimal La loading and Ni-Mo composition that maximise product yield and improve deoxygenation and desulfurization efficiencies have not been well explored. Although several authors have investigated the use of Ni-Mo catalysts promoted with La for bio-oil upgrading, the influence of varying Ni/Mo ratios at different La loadings on these three metrics – bio-oil yield, deoxygenation, and desulfurization – has not been extensively studied, representing a critical research gap. This research investigates the influence of the Ni/Mo ratio at varying La loadings on yield, deoxygenation, and desulfurization of bio-oil during in-situ rice bran pyrolysis using clay-supported Ni-Mo catalysts. Clay, a highly abundant mineral, was chosen as the catalyst support material due to its high thermal stability and significantly high surface area. The incorporation of the La promoter into the clay matrix enhances its basicity, improves metal dispersion, and reduces sintering tendencies (Garbarino et al., 2019; Boukha et al., 2022). Understanding the influence of the Ni/Mo ratio and La loading in clay-supported Ni-Mo catalysts will enable precise tuning of their performance to maximise product yield, deoxygenation, and desulfurisation, thereby reducing material and energy demands in post-pyrolysis bio-oil upgrading and enhancing process economic viability.\u003c/p\u003e"},{"header":"2. METHODOLOGY","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Material Preparation and Chemicals used\u003c/h2\u003e\u003cp\u003eLocal clay samples was obtained from Oleh, a swampy community in the Niger Delta region of Nigeria. The wet clay sample was sun-dried for 3 days and further oven-dried at 110 \u003csup\u003eo\u003c/sup\u003eC for 6 hrs to reduce its moisture content. Nickel nitrate (Ni(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e.6H\u003csub\u003e2\u003c/sub\u003eO), lanthanum nitrate (La(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e.6H\u003csub\u003e2\u003c/sub\u003eO), and ammonium molybdate ((NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eMo\u003csub\u003e4\u003c/sub\u003e.4H2O) used as precursors for Ni, La, and Mo respectively were obtained in analytical grade and were used without further purification. Distilled water was used as solvent in preparing the different concentrations of the metal salts. Clay was chosen as the catalyst support due to its relatively high surface area and thermal stability.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Catalyst Preparation\u003c/h2\u003e\u003cp\u003eThis research employed the method of incipient wetness in impregnating the metal salts into the clay support. The impregnation of the different metals was sequentially carried out using varying weights of the metal precursors to achieve the desired compositions. In order to enhance the promoting effect of La, the metal loading process on the clay began with the impregnation of La, and this was followed by nickel and then molybdenum. Adding La as the last step could reduce the catalytic activity due to the blockage of active sites (Vandevyvere et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). The dried clay sample was subjected to La modification using La(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e.6H\u003csub\u003e2\u003c/sub\u003eO, dried at 110\u0026deg;C for 6 hours to remove residual moisture before it was calcined at 600\u0026deg;C for 4 hours in order to fix La onto the clay support and promote metal-support interactions. The La-loaded clay sample was subjected to nickel impregnation and then Mo impregnation, following the same procedure outlined in La-loading. The high temperature in the calcination step helps in converting the metal salts into their corresponding oxide forms, fixing them to the support, and creating stable and active Ni and Mo catalytic phases. The active Ni and Mo phases provide the catalytic properties in the pyrolysis process.\u003c/p\u003e\u003cp\u003eBased on the varying amounts of metals used in formulating the catalysts, 15 catalysts samples were obtained as presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eMetal loadings used in the catalysts formulations\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSeries\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNi loading (wt%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMo loading (wt%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"4\" rowspan=\"5\"\u003e\u003cp\u003e1 wt % La\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eB\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eE\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"4\" rowspan=\"5\"\u003e\u003cp\u003e2 wt % La\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eB\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eE\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"4\" rowspan=\"5\"\u003e\u003cp\u003e3 wt % La\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eB\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eE\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Catalyst Characterization\u003c/h2\u003e\u003cp\u003eThe prepared catalysts were characterized using Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), and the Brunauer-Emmett-Teller (BET) analysis. The FTIR analysis was employed to identify the surface functional groups present in the catalysts (Orugba \u0026amp; Edomwonyi, 2023), while the SEM provides the morphology and particle distribution. The specific surface area was determined using the BET model (Brunauer et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1938\u003c/span\u003e), and the pore size and volume were determined using the Barret-Joyner-Halenda (BJH) method (Barrett et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1951\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Pyrolysis Experiments\u003c/h2\u003e\u003cp\u003eThe prepared rice bran (biomass samples) was subjected to intermediate pyrolysis in a fixed-bed reactor heated with an electric heater at a heating rate of 30\u0026deg;C/min, a temperature of 450\u0026deg;C, a residence time of 10 minutes, and a nitrogen flow rate of 1.5 L/min to maintain an inert atmosphere. For all pyrolysis experiments, 2 g of catalyst was weighed and thoroughly mixed with 20 g of biomass feedstock. The vapour from the pyrolyser was passed through a condenser where liquid components were condensed and collected as bio-oil and weighed, while the uncondensed vapours were flared. At the end of each pyrolysis experiment, the char was collected from the reactor and weighed. The mass of bio-oil and char was measured directly and converted to percentage yields as shown in Equations \u003cspan refid=\"Equ1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Equ2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, respectively, while the gas yield was calculated as the balance according to Eq.\u0026nbsp;\u003cspan refid=\"Equ3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:{Y}_{Bio-Oil}\\left(\\%\\right)=\\:\\frac{\\:mass\\:of\\:Bio-oil\\:\\left(g\\right)}{mass\\:of\\:biomass\\:\\left(g\\right)}\\:\\text{x}\\:100\\:\\:\\:\\:\\:\\:$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\:{Y}_{Char}\\left(\\%\\right)=\\:\\frac{\\:mass\\:of\\:char\\:\\left(g\\right)}{mass\\:of\\:biomass\\:\\left(g\\right)}\\:\\text{x}\\:100\\:\\:\\:\\:\\:\\:\\:$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equ3\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ3\" name=\"EquationSource\"\u003e\n$$\\:{Y}_{gas}\\left(\\%\\right)=\\:\\:100\\text{\\%}-{Y}_{Bio-Oil}\\left(\\%\\right)-\\:{Y}_{Char}\\left(\\%\\right)\\:$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e3\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e2.5 Characterization of Bio-Oil\u003c/h2\u003e\u003cp\u003eIn order to obtain the catalyst sample that produced the highest degree of deoxygenated bio-oil, the bio-oil elemental analysis was carried out using a CHNS elemental analyser. The bio-oil carbon, hydrogen, nitrogen, and sulphur contents were determined directly, while oxygen content was calculated by difference. Deoxygenation efficiency was evaluated as the reduction in the bio-oil oxygen content relative to the raw biomass according to Eq.\u0026nbsp;\u003cspan refid=\"Equ4\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003cdiv id=\"Equ4\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ4\" name=\"EquationSource\"\u003e\n$$\\:Deoxygenation\\:\\left(\\%\\right)=\\frac{{O}_{biomass}-{O}_{bio-oil}}{{O}_{biomass}}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e4\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ewhere O\u003csub\u003ebiomass\u003c/sub\u003e is the oxygen content of the biomass and O\u003csub\u003ebio\u0026minus;oil\u003c/sub\u003e is the bio-oil oxygen content.\u003c/p\u003e\u003cp\u003eFurther analyses of the most deoxygenated bio-oil sample were carried out. The FTIR analysis was carried out to determine the functional groups present in the bio-oil, while its composition was analysed using the gas chromatography-mass spectrometry (GC-MS) (Thermo Scientific, Austin, TX, USA). Product yields were tabulated and visualised using bar charts to evaluate the effect of La content (1\u0026ndash;3 wt%) across the catalyst series. Statistical analysis was conducted to identify trends and correlations between catalyst composition and product distribution.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. RESULTS AND DISCUSSIONS","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Results of Catalyst Characterization\u003c/h2\u003e\u003cp\u003eThe results of the different characterisation techniques employed in the characterisation of the catalysts are presented in this section.\u003c/p\u003e\u003cdiv id=\"Sec10\" class=\"Section3\"\u003e\u003ch2\u003e3.1.1 FTIR Results of the Catalysts\u003c/h2\u003e\u003cp\u003eThe summary table of the FTIR analysis of the catalyst sample D2, which produced the highest degree of deoxygenation, is presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eFTIR summary table of the catalysts\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePeaks (cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eGroups\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMolecular motion\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eType of vibration\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3436.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlcohol\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eO-H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch, H-bonded\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2926.42\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlkanes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC-H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2858.93\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlkanes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC-H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1741.73\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAldehydes/ ketones\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC\u0026thinsp;=\u0026thinsp;O\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1633.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlkenes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC\u0026thinsp;=\u0026thinsp;C\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1456.78\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAromatics\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC\u0026thinsp;=\u0026thinsp;C\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1372.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlkanes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC-H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eBending\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1239.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eEther\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC-O\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1163.85\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTertiary alcohol\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC-O\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1103.81\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePrimary alcohol\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC-O\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e723.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAromatic/ aldehyde\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC-H/ C-Cl\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOut-of-plane bend/ stretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e465.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMetal-oxide\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eM-O\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eAs revealed in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, a broad band at 3436 cm⁻\u0026sup1; indicates the presence of hydroxyl groups of alcohols or phenols, usually associated with high hydrogen bonding capacity. The peaks at 2926.42 cm⁻\u0026sup1; and 2858.93 cm⁻\u0026sup1; indicate C-H stretching from alkane groups. The band at 1741.73 cm⁻\u0026sup1; represents C\u0026thinsp;=\u0026thinsp;O stretching, indicating the presence of aldehydes or ketones. The peak at 1633 cm⁻\u0026sup1; indicates C\u0026thinsp;=\u0026thinsp;C stretching in aromatics or alkenes, while C-H bending of alkanes is depicted by 1372 cm⁻\u0026sup1;.. C-O stretching of esters, tertiary, and primary alcohols were respectively depicted by 1239, 1163.85, and 1103.81 cm⁻\u0026sup1; peaks, which promotes catalytic activity. The 723.23 cm⁻\u0026sup1; band suggests the presence of metal-oxide vibrations, likely from oxides of Ni, Mo, or La. These metal oxides formed on the catalyst's surface are essential for enhancing catalytic activity and stability.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section3\"\u003e\u003ch2\u003e3.1.2 Results of Catalysts BET Analysis\u003c/h2\u003e\u003cp\u003eThe summary of the catalysts BET analysis is presented in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eBET Analysis of the Catalyst\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameter/ unit\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eValue\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBET surface area (m\u003csup\u003e2\u003c/sup\u003e/g)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e205.45\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTotal pore volume (m\u003csup\u003e3\u003c/sup\u003e/g)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.6055\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBJH desorption pore volume (m\u003csup\u003e3\u003c/sup\u003e/g)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.5222\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAverage pore diameter (BJH desorption) (nm)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e3.022\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBET pore diameter (adsorption) (nm)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2.754\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eFrom the summary of the catalyst BET analysis presented in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, the catalyst has a large specific surface area of 205.45 m\u0026sup2;/g, indicating a large number of active sites. The catalyst's total pore volume of 0.655 m\u0026sup3;/g and a BJH pore volume of 0.5222 m\u0026sup3;/g revealed its mesoporous structure. The pore diameter obtained from BJH desorption (3.022 nm) and BET adsorption pore diameter (2.754 nm) implies the catalyst has a well-developed mesoporous structure that promotes catalytic activities.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section3\"\u003e\u003ch2\u003e3.1.3 Results of Catalysts SEM Analysis\u003c/h2\u003e\u003cp\u003eThe SEM micrograph of the synthesized catalysts is presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe SEM image of the catalysts shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003e revealed a highly porous clay matrix with irregular voids. This structural arrangement of the catalysts also supports the mesoporous structure inferred from BET analysis. The spongy morphology of the catalyst's surface may be due to the metal-oxide dispersion, which may have contributed to the creation of an open, channel-like network, a very desirable feature that promotes catalytic activity as it allows for accessibility and easy diffusion of reactant molecules throughout the catalyst matrix.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Pyrolysis Product Yield\u003c/h2\u003e\u003cp\u003eThe product yield distribution obtained from the catalytic pyrolysis of the rice bran is presented in Figs.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAs revealed in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e2\u003c/span\u003e, pyrolysis product yield \u0026ndash; oil, char, and gas \u0026ndash; varies significantly with change in catalyst metal loading; hence, the desired product yield can be controlled via Ni/Mo ratio tuning and La weight regulation. The pyrolysis experiment carried out without a catalyst (control sample) produced the least bio-oil and highest char yields, while the catalyst series C (6 wt% Ni, 6 wt% Mo) demonstrated superior performance over other catalyst formulations in oil and char yields, especially at 1 wt% La loading, producing 28.23% oil and 47.77% char. The performance of catalyst sample C may be due to the balanced Ni/Mo ratio: Ni promotes deoxygenation and stabilises oil-phase intermediates, thus reducing secondary cracking, while Mo enhances char formation via condensation and polymerisation. As Ni outweighs Mo content (series D and E), the Ni/Mo balance was observed to shift, as oil yield falls while gas yield (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e4\u003c/span\u003e) increases. This shows that high Ni content promotes excessive cracking, especially at low Mo due to low Mo stabilisation influence. Similar results were obtained by Ahmad et al. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) and Quindimil et al. (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAs La content was increased to 2 wt%, more char is produced, producing the highest char of 51.8% but low oil yield. This implies that at moderate levels of La, the catalyst basicity is enhanced to promote solid-phase stability. However, further increasing La to 3 wt% produced a declined char yield. Catalysts of series B and D with low Mo content showed very high gas yields (50.46 and 47.4%, respectively) and low oil and char yields, revealing the dual nature of La. Moderate La promotes polymerisation and char-forming tendency; higher loadings shift the catalyst's acidity to favour cracking (Escobar et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), producing more gases. Thus, a balanced Ni/Mo at moderate La loadings (1\u0026ndash;2 wt%) is the best catalyst formulation for maximising oil yield.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Degree of Deoxygenation (DoD) of Bio-oil\u003c/h2\u003e\u003cp\u003eSince low oxygen content is a key parameter in producing quality bio-oil, the oxygen-removal tendency of any catalyst is very important in formulating a catalyst for biomass pyrolysis. The degree of deoxygenation (DoD) of the bio-oil obtained using different catalyst formulations with varied Ni/Mo/La metal loadings is presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAs depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e5\u003c/span\u003e, low La loading of 1 wt% in series C (6 wt% Ni, 6 wt% Mo) and D (8 wt% Ni, 4 wt% Mo) produced the highest degree of deoxygenation (DoD) values of 69.95% and 74.46%, respectively, revealing Ni's role in promoting hydrodeoxygenation. For series C, the Ni/Mo ratio provides optimal conditions for hydrodeoxygenation due to the synergistic effect of Ni/Mo: Ni promoting deoxygenation and Mo promoting the stability of Ni particles. At 1 wt% La loading, catalysts of series A (2 wt% Ni, 10 wt% Mo) and B (4 wt% Ni, 8 wt% Mo) produced lower bio-oil DoD values of 38.3% and 36.11%, respectively. The high Mo content and low Ni content limit the number of available active sites for hydrogenation, resulting in incomplete deoxygenation. This implies that Mo alone is less effective for HDO and must require Ni activation to produce sufficient hydrogenation.\u003c/p\u003e\u003cp\u003eAt moderate La loading (2 wt%), the bio-oil DoD was significantly increased, especially for catalyst D2 (8 wt% Ni, 4 wt% Mo, 2 wt% La), producing the highest DoD of 89%. This high performance of catalyst D2 suggests that La is a good structural promoter, improving metal dispersion, reducing sintering tendency, and enhancing basicity on the catalyst surface (Garbarino et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Boukha et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), which is necessary for adsorption and conversion of oxygen groups. Catalyst C remaining stable at 70% further confirms the robustness of the balanced Ni/Mo ratio even at various La loadings. However, the low DoD demonstrated by catalyst B (24.57%) revealed that the promoting effect of La alone cannot compensate for a poorly balanced Ni/Mo ratio. The moderate increase in DoD for catalyst series A (49.16%) and E (55.91%) also confirms that La improves the catalytic activity at sufficiently high Ni.\u003c/p\u003e\u003cp\u003eAt 3 wt% La, catalyst sample C dominates, producing 81%, while a decline to 71.1% and 60.65% was observed for D and E, respectively. This may be due to either the very high Ni loading, which leads to deactivation due to increased sintering and coke-forming tendencies (Ahmad et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Quindimil et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), or the high La loading that reduces acidity by covering acidic sites with the basic La₂O₃ (Escobar et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). This result revealed that Ni is the primary metal responsible for deoxygenation (Nuhma et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Kristensen et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), while Mo plays the supporting role of maintaining catalyst structure and regulating acidity, and La in moderate loading improves metal dispersion and supports HDO activity (Garbarino et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Escobar et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\u003ch2\u003e3.4 Degree of Desulfurization (DDS) of Bio-oil\u003c/h2\u003e\u003cp\u003eThe degree of desulfurization of the bio-oil from the pyrolysis process using the various catalyst samples is presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e6\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAs depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e6\u003c/span\u003e, sulphur removal is strongly influenced by Ni/Mo loading at different La weights. At 1 wt% La, the highest sulphur removal of 78.38% was obtained using catalyst sample C (6 wt% Ni, 6 wt% Mo), and this is closely followed by catalyst samples B and D, while catalyst sample E with the least content of Mo (2 wt%) and highest Ni (10 wt%) produced the lowest degree of sulphur removal (35.14%). This clearly revealed that a balanced Ni/Mo weight ratio favours sulphur removal, as Ni promotes hydrodeoxygenation and C-S bond cleavage, while Mo supports the adsorption of sulphur and promotes Ni site stabilisation, as reported by several authors (Liu et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Zhu et al., \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Wang et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eOn increasing La to 2 wt%, a significant boost in sulphur removal (84%) was recorded using catalyst sample A with low Ni (2 wt%) and high Mo (10 wt%), while samples C and D also performed very well, reaching values above 81%. At moderately high La loading, increasing the Mo loading produced a significant reduction in sulphur content since the La dispersion is improved (Garbarino et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Boukha et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), thus enhancing its sulphur adsorbing power (Wang et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Even the performance of catalyst sample E that was very poor at 1 wt% La was highly increased to 67.5% at 2 wt% La, which further confirms that a relatively high La content in the catalyst could offset low Mo content. As La was increased to 3 wt%, the performances of the catalyst samples were also enhanced, with sample D producing 83.7% sulphur removal and even E still increasing to 78.33%. Thus, it could be inferred that a very high La content in the catalyst sample may offset the low Mo loading and promote desulfurization. However, the slight decline in catalysts sample C to 70.27% may be due to excess La covering active sites.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003e3.4 Bio-Oil Characterization\u003c/h2\u003e\u003cdiv id=\"Sec17\" class=\"Section3\"\u003e\u003ch2\u003e3.4.1 Physichochemical Properties of Bio-Oil\u003c/h2\u003e\u003cp\u003eA comparative analysis of fuel properties of the bio-oil obtained from uncatalyzed pyrolysis (control) and the catalyzed pyrolysis using the catalysts sample D2- sample that produced the highest degree of deoxygenation are presented in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003ePhysicochemical properties of bio-oils from the catalyzed and uncatalyzed pyrolysis\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eProperty/ Units\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eControl\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCatalyzed oil\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAcid Value (mg KOH/g)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e14.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.76\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAsh Content (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.01\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCalorific Value (MJ/kg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e32\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDensity (g/cc)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.06\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.85\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFlash Point (\u003csup\u003eo\u003c/sup\u003eC)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e115\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e120\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMoisture content (wt%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003epH\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3.69\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.31\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePour Point (\u003csup\u003eo\u003c/sup\u003eC)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eViscosity (cSt)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.21\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe bio-oil obtained from the catalysed pyrolysis has superior fuel properties compared with the bio-oil from the uncatalysed pyrolysis. The acid value of the bio-oil from the catalysed pyrolysis, with a value of 6.76, is significantly lower than the value of 14.18 obtained for the uncatalysed process. A lower acidity value enhances bio-oil stability and reduces corrosivity. The lower ash content (0.01%), higher energy value (32 MJ/kg), and the relatively low density (0.85 g/cc) of the bio-oil from the catalysed process bring its quality closer to the range of diesel fuels (Suhaimia et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Furthermore, the bio-oil from the catalysed pyrolysis has lower moisture content (15%) and a higher flash point (120\u0026deg;C), indicating its better fuel qualities.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec18\" class=\"Section3\"\u003e\u003ch2\u003e3.4.2 FTIR Analysis of Bio-Oil\u003c/h2\u003e\u003cp\u003eThe FTIR peaks representing the different functional groups present in the bio-oil obtained from the catalysed pyrolysis are presented in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eFTIR summary table of the bio-oil\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePeaks (cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eGroups\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMolecular motion\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eType of vibration\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4336.51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eO\u0026ndash;H (water, alcohol)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eO\u0026ndash;H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch, H-bonded\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4196.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eO\u0026ndash;H (alcohol/phenol)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eO\u0026ndash;H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3781.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFree O\u0026ndash;H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eO\u0026ndash;H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3749.17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFree O\u0026ndash;H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eO\u0026ndash;H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3409.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlcohol/Phenol\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eO\u0026ndash;H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch, H-bonded\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3344.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlcohol/Phenol\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eO\u0026ndash;H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch, H-bonded\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2927.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlkanes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC\u0026ndash;H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2861.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlkanes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC\u0026ndash;H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2067.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlkyne/C\u0026thinsp;\u0026equiv;\u0026thinsp;C\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC\u0026thinsp;\u0026equiv;\u0026thinsp;C\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2038.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlkyne/C\u0026thinsp;\u0026equiv;\u0026thinsp;C\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC\u0026thinsp;\u0026equiv;\u0026thinsp;C\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1725.62\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAldehydes/Ketones/Carboxylic acids\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC\u0026thinsp;=\u0026thinsp;O\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1450.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlkanes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCH₂/CH₃\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eBending\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1239.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eEsters/Ethers\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC\u0026ndash;O\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1174.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePrimary alcohol\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC\u0026ndash;O\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e951.63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlkenes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e=C\u0026ndash;H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOut-of-plane bend\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e719.34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAromatic/alkane\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC\u0026ndash;H (CH₂ rocking)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eBending\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e413.99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMetal\u0026ndash;oxide residue\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eM\u0026ndash;O\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStretch\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe bio-oil FTIR summary table presented in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e revealed a complex chemical composition with different functional groups. The broad bands between 4336 and 3344 cm⁻\u0026sup1; represent the OH vibrations associated with alcohols and phenols (Dai et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Peaks at 2927 and 2861 cm⁻\u0026sup1; depicting CH groups suggest the presence of alkanes, which enhances the fuel properties of the bio-oil. Peaks at 2067 and 2038 cm⁻\u0026sup1; indicate the occurrence of C\u0026thinsp;\u0026equiv;\u0026thinsp;C groups, while the peak at 1726 cm⁻\u0026sup1; indicates C\u0026thinsp;=\u0026thinsp;O stretching vibrations of ketones, aldehydes, or carboxylic acids (Saito et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Other prominent groups detected in the bio-oil include C-O stretching of esters, ethers, and primary alcohols represented by 1239 and 1174 cm⁻\u0026sup1;.. Despite the high degree of deoxygenation recorded by the catalysts, the bio-oil needs upgrading to further reduce the quantity of oxygenated compounds and hence, raise its fuel properties.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec19\" class=\"Section3\"\u003e\u003ch2\u003e3.4.3 Result of the Bio-Oil GC-MS Analysis\u003c/h2\u003e\u003cp\u003eThe GC-MS analysis of the bio-oil obtained from the catalyzed pyrolysis is presented in Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eGC-MS Analysis of the bio-oil\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eS/No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRT (mins)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCompound Name\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eArea %\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e5.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eOctane\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.20\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e7.70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eDecanoic acid\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.60\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e12.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1-undecene\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3.60\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e13.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1-dodecene\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.65\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e18.40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eDodecene\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e8.60\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e19.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1, 12-tridecadiene\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.20\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e23.70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3-tetradecene\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e10.50\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e25.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTridecane\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e16.30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e34.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3-tetradecane\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e10.20\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e29.42\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3-tetradecene\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2.65\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e38.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eHexadecane\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e5.20\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e40.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCyclohexane, 1,5-diisopropyl-2,3-dimethyl\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.22\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e42.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1-hexadecene\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3.60\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e45.40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMethyl-hexadecadienoate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e45.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eIsopropylmyristate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3.65\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e46.40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3-octadecanone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.70\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e53.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1-octadecanethiol\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.15\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e55.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMethyllinolelaidate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e4.60\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e65.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMethylelaidate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e5.30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e62.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMethyl-octadecenoate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.07\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e57.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1-docosene\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.12\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe GC-MS result of the bio-oil presented in Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e represents a complex system of 21 compounds, predominantly long-chain hydrocarbons. The major compounds revealed by the GC-MS analysis include tridecane, tetradecane, tetradecene, and hexadecane. These diesel-range paraffins and olefins (Knobloch et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) might have contributed significantly to the high calorific value of the bio-oil. However, the bio-oil still contains some amount of alkenes and dienes, indicating some level of unsaturation.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"4. CONCLUSION","content":"\u003cp\u003eA study to investigate the performance of La-promoted Ni-Mo/clay catalysts to obtain low-oxygen and low-sulphur bio-oil in the in-situ pyrolysis of rice bran has been carried out. The optimised mesoporous catalysts with a surface area of 205.45 m\u0026sup2;/g have well-developed active sites for high catalytic activities and obtained an optimal bio-oil yield of 28.23% at a balanced 1:1 Ni/Mo ratio and at 1 wt% La loading. At this configuration, the synergistic effect of the hydrogenation ability of Ni and the cracking tendency of Mo is optimised. Slightly increasing La loading to 2 wt% promotes sulphur removal due to the improved metal dispersion, ensuring optimal performance of Mo in active site stability and promoting C-S bond cleavage activities of Ni. Optimum deoxygenation was achieved at a higher Ni/Mo ratio (2:1) and moderate La loading (2 wt%). The relatively high La concentration improved metal dispersion, reducing the sintering tendency and enhancing basicity, which favours the ability of Ni to adsorb and convert oxygen. These well-tailored Ni-Mo/La-formulated catalysts can significantly reduce oxygen and sulphur contents of bio-oil in the pyrolysis stage and hence reduce the complexity and cost of post-pyrolysis upgrades.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eHDO\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ehydrodeoxygenation\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eY\u003csub\u003eBio\u003c/sub\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eoil-bio-oil yield\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eY\u003csub\u003eChar\u003c/sub\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eBiochar yield\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eY\u003csub\u003egas\u003c/sub\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eGas yield\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eO\u003csub\u003ebiomass\u003c/sub\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ebiomass oxygen content\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eO\u003csub\u003eoil\u003c/sub\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eoil oxygen content\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eDoD\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003edegree of deoxygenation\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eDDS\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003edegree of desulfurization\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics and Consent to Participate\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study did not involve human participants, animals, or any other subjects requiring ethical approval or consent.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for Publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAs the sole author, I consent to the publication of this manuscript and its associated data in Catalysis Letters. No human participants or other entities requiring consent were involved in this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interest\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe author declares no competing interests, financial or non-financial, that could influence the research or its outcomes\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAs the sole author, Henry O. Orugba conceived the study, designed the experiments, prepared and characterized the catalysts, conducted the pyrolysis experiments, analyzed the data, interpreted the results, and wrote the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding Declaration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe author did not receive any funding for this research work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available upon reasonable request. Please contact the corresponding author Dr H.O Orugba at [email protected] to inquire about access to the data.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eI sincerely acknowledge my 2024/2025 final-year students in the Department of Chemical Engineering under my supervision for their technical assistance in catalyst synthesis and their helpful discussions.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAhmad M., Farhana R., Raman A.A.A., Bhargava S.K. (2016). Synthesis and activity evaluation of heterometallic nano oxides integrated ZSM-5 catalysts for palm oil cracking to produce biogasoline. Energy Conversion and Management, 119, 352\u0026ndash;360.\u003c/li\u003e\n \u003cli\u003eAyala-Cort\u0026acute;es A., Torres D., Frecha E., Arcelus-Arrillaga P., Villafan-Vidales H.I.,\u0026acute;\u003cbr\u003eLongoria A., Pinilla J.L., Suelves I. (2023). Upgrading of biomass-derived solar\u003cbr\u003ehydrothermal bio-oils through catalytic hydrodeoxygenation in supercritical\u003cbr\u003eethanol, Journal of Environmental Chemical Engineering, 11 (6), 111395, https://doi.org/10.1016/j.\u003cbr\u003ejece.2023.111395.\u003c/li\u003e\n \u003cli\u003eBarrett E. P., Joyner L. G., Halenda P. P. (1951). The Determination of Pore Volume and Area Distributions in Porous. I. Computations from Nitrogen Isotherms. Journal of American Chemical Society, 73, 373\u0026minus;380.\u003c/li\u003e\n \u003cli\u003eBoukha Z., Bermejo-Lopez A., Pereda-Ayo B., Gonzalez-Marcos J.A., Gonzalez-Velasco J.R. (2022). Study on the promotional effect of lanthana addition on the performance of hydroxyapatite-supported Ni catalysts for the CO\u003csub\u003e2\u003c/sub\u003e Methanation Reaction. Applied Catalysis B-Environmental, 314, 121500\u003c/li\u003e\n \u003cli\u003eBrunauer S., Emmett P. H., Teller E. (1938). Adsorption of Gases in Multimolecular Layers. Journal of American Chemical Society, 60, 309\u0026minus;319.\u003c/li\u003e\n \u003cli\u003eda Silva T.L., Dutra F., Marques S., Gomes M., Costa P., Paradela F., Ferreira F.C., Faria N.T., Mugica P., Pinheiro H.M. et al. (2025). Production of sustainable aviation fuel precursors using the oleaginous yeast Rhodotorula toruloides PYCC 5615 cultivated on eucalyptus bark hydrolysate. Biomass Bioenergy, 197, 107790.\u003c/li\u003e\n \u003cli\u003eDai, F., Zhuang, Q., Huang, G., Deng, H., \u0026amp; Zhang, X. (2023). Infrared Spectrum Characteristics and Quantification of OH Groups in Coal. ACS Omega, 8, 17064 - 17076. https://doi.org/10.1021/acsomega.3c01336.\u003c/li\u003e\n \u003cli\u003edi Vito Nolfi G., Gallucci K., Rossi L. (2021). Green Diesel Production by Catalytic Hydrodeoxygenation of Vegetables Oils. International Journal of Environmental Research and Public Health, 18, 13041\u003c/li\u003e\n \u003cli\u003eDing W., Li H., Zong R., Jiang J., Tang X. (2021). Controlled Hydrodeoxygenation of Biobased Ketones and Aldehydes over an Alloyed Pd\u0026ndash;Zr Catalyst under Mild Conditions. ACS Sustainable Chemistry and Engineering, 9, 3498\u0026ndash;3508.\u003c/li\u003e\n \u003cli\u003eDuan, Y. (2017). Synthesis of Renewable Diesel Range Alkanes by\u003cbr\u003eHydrodeoxygenation of Palmitic Acid over 5% Ni/CNTs under Mild\u003cbr\u003eConditions. Catalysts 7 (12), 81. doi:10.3390/catal7030081\u003c/li\u003e\n \u003cli\u003eEscobar J., Barrera M. C., Santes V. F., Fouconnier B. (2023). Guaiacol HDO on La-modified Pt/Al2O3: Influence of rare-earth loading. Canadian Journal of Chemical Engineering, 101, 5772\u0026minus;5784.\u003c/li\u003e\n \u003cli\u003eGarbarino G., Wang C., Cavattoni T., Finocchio E., Riani P., Flytzani- Stephanopoulos M., Busca G. (2019). A study of Ni/La-Al2O3 catalysts: a competitive system for CO2 methanation. Applied Catalysis B-Environmental, 248, 286\u0026ndash;297\u003c/li\u003e\n \u003cli\u003eHan, J., Duan, J., Chen, P., Lou, H., Zheng, X., and Hong, H. (2012). CarbonSupported Molybdenum Carbide Catalysts for the Conversion of Vegetable\u003cbr\u003eOils. ChemSusChem 5 (4), 727\u0026ndash;733. doi:10.1002/cssc.201100476\u003c/li\u003e\n \u003cli\u003eKandel, K., Anderegg, J. W., Nelson, N. C., Chaudhary, U., and Slowing, I. I. (2014).\u003cbr\u003eSupported Iron Nanoparticles for the Hydrodeoxygenation of Microalgal Oil to\u003cbr\u003eGreen Diesel. Journal of Catalysis, 314, 142\u0026ndash;148. doi:10.1016/j.jcat.2014.04.009\u003c/li\u003e\n \u003cli\u003eKnobloch, M., Schinkel, L., Schilling, I., Kohler, H., Lienemann, P., Bleiner, D., \u0026amp; Heeb, N. (2021). Transformation of short-chain chlorinated paraffins by the bacterial haloalkane dehalogenase LinB - Formation of mono- and di-hydroxylated metabolites. Chemosphere, 262, 128288 . https://doi.org/10.1016/J.CHEMOSPHERE.2020.128288.\u003c/li\u003e\n \u003cli\u003eKristensen T.A., Hulterberg C.P., Wallenberg R.L., Abdelaziz O.Y., Blomberg S. (2024). Promoting Effect of Ce and La on Ni\u0026minus;Mo/\u0026delta;-Al2O3 Catalysts in the Hydrodeoxygenation of Vanillin. Energy and Fuels, 38(11), 9827-9835. https://doi.org/10.1021/acs.energyfuels.4c00898\u003c/li\u003e\n \u003cli\u003eLeyva, C., Rana, M. S., Trejo, F., and Ancheyta, J. (2007). On the Use of Acid-BaseSupported Catalysts for Hydroprocessing of Heavy Petroleum. Industrial and Engineering Chemistry Research, 46 (23), 7448\u0026ndash;7466. doi:10.1021/ie070128q\u003c/li\u003e\n \u003cli\u003eLiu, X., Yan, J., Mao, J., He, D., Yang, S., Mei, Y., \u0026amp; Luo, Y. (2021). Inhibitor, co-catalyst, or intermetallic promoter? Probing the sulfur-tolerance of MoOx surface decoration on Ni/SiO2 during methane dry reforming. Applied Surface Science, 548, 149231. https://doi.org/10.1016/J.APSUSC.2021.149231.\u003c/li\u003e\n \u003cli\u003eMunoz-Arjona A., Ayala-Cortes A., Di Stasi C., Torres D., Pinilla J.L., Suelves I.C. (2023). Catalytic hydrodeoxygenation of waste cooking oil into green diesel range\u003cbr\u003ehydrocarbons: From batch to continuous processing. Chemical Engineering Journal 503, 158303. https://doi.org/10.1016/j.cej.2024.158303\u003c/li\u003e\n \u003cli\u003eNuhma, M. J., Alias, H., Tahir, M., \u0026amp; Jazie, A. A. (2022). Catalytic Deoxygenation of Hydrolyzed Oil of Chlorella Vulgaris Microalgae over Lanthanum-Embedded HZSM-5 Zeolite Catalyst to Produce Bio-Fuels. \u003cem\u003eMolecules\u003c/em\u003e\u003cem\u003e,\u003c/em\u003e \u003cem\u003e27\u003c/em\u003e(19), 6527. https://doi.org/10.3390/molecules27196527\u003c/li\u003e\n \u003cli\u003eOrugba H. O., Osagie C., Owamah H. I., Edomwonyi-Otu L. C. (2024). Sustainable Faecal Sludge Management in Internally Displaced Persons (IDPs) Settlements in Tropical Climate: A Review. Nigerian Journal of Technology, 43(1), 172 \u0026ndash; 188; \u003cem\u003ehttps://doi.org/10.4314/njt.v43i1. 19\u003c/em\u003e\u003c/li\u003e\n \u003cli\u003eOrugba H.O., Edomwonyi-Otu L.C. (2023). Improving the Activity and Stability of Turtle Shell-derived Catalyst in Alcoholysis of Degraded Vegetable Oil: An Experimental Design Approach. Journal of King Saud University-Engineering Science, 35(4), 975-303. doi: 10.1016/j.jksues.2021.05.001.\u003c/li\u003e\n \u003cli\u003ePastor-P\u0026eacute;rez L., Jin W., Villora-Pic\u0026oacute; J.J., Wang Q., Pastor-Blas M.M., Sep\u0026uacute;lveda-Escribano A., Reina T.R. (2021). H\u003csub\u003e2\u003c/sub\u003e-free demethoxylation of guaiacol in subcritical water using Pt supported on N-doped carbon catalysts: A cost-effective strategy for biomass upgrading. Journal of Energy Chemistry, 58, 377\u0026ndash;385\u003c/li\u003e\n \u003cli\u003ePatil, S. J., and Vaidya, P. D. (2018). On the Production of Bio-Hydrogenated Diesel\u003cbr\u003eover Hydrotalcite-like Supported Palladium and Ruthenium Catalysts. Fuel\u003cbr\u003eProcessing Technology, 169, 142\u0026ndash;149. doi:10.1016/j.fuproc.2017.09.026\u003c/li\u003e\n \u003cli\u003ePerea-Moreno, M.-A.; Samer \u0026oacute;n-Manzano, E.; Perea-Moreno, A.-J. Biomass as Renewable Energy: Worldwide Research Trends. Sustainability 2019, 11, 863.\u003c/li\u003e\n \u003cli\u003eQu L., Jiang X., Zhang Z., Zhang X.-G., Song G.-Y., Wang H.-L., Yuan Y.-P., Chang Y. L. (2021). A review of hydrodeoxygenation of bio-oil: Model compounds, catalysts, and equipment. Green Chemistry, 23, 9348\u0026ndash;9376.\u003c/li\u003e\n \u003cli\u003eQuindimil A., De-La-Torre U., Pereda-Ayo B., Gonz\u0026acute;alez-Marcos J.A., Gonz\u0026acute;alez- Velasco J.R. (2018). Ni catalysts with La as promoter supported over Y- and BETA- zeolites for CO2 methanation, Applied Catalysis B-Environmental, 238, 393\u0026ndash;403.\u003c/li\u003e\n \u003cli\u003eRanga C., L\u0026oslash;deng R., Alexiadis V.I., Rajkhowa T., Bj\u0026oslash;rkan H., Chytil S., Svenum I.H., Walmsley J., Detavernier C., Poelman H., Voort P.V.D., Thybaut J.W. (2018). Effect of composition and preparation of supported MoO\u003csub\u003e3\u003c/sub\u003e catalysts for anisole hydrodeoxygenation. Chemical Engineering Journal, 335,120-132.\u003c/li\u003e\n \u003cli\u003eRueda A.C., Granados-Reyes J., Delaunay J., Mora-Masi \u0026agrave; P., Cesteros Y. (2025). Tuning the acid base properties of layered double hydroxides for the selective obtention of cyclohexane and cyclohexanol in the hydrodeoxygenation of guaiacol. Chemical Engineering Journal, 512, 162226.\u003c/li\u003e\n \u003cli\u003eSaidi M, Baharan S.N.R. (2020). Kinetic modeling and experimental investigation of hydro-catalytic upgrading of anisole as a model compound of bio-oils derived from fast pyrolysis of lignin over Co/ g-Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e. Chemistry, 5, 2379-2387.\u003c/li\u003e\n \u003cli\u003eSaidi M., Rahzani B., Rahimpour M.R. (2017). Characterization and catalytic properties of molybdenum supported on nano gamma Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e for upgrading of anisole model compound. Chemical Engineering Journal,319,143-154.\u003c/li\u003e\n \u003cli\u003eSaidi M., Safaripour M. (2021). Ni\u0026ndash;Mo nanoparticles stabilized by ether functionalized ionic polymer: A novel and efficient catalyst for hydrodeoxygenation of 4-methylanisole as a representative of lignin-derived pyrolysis bio-oils. International Journal of Hydrogen Energy, 46(2), 2191-2203.\u003c/li\u003e\n \u003cli\u003eSaito, K., Xu, T., \u0026amp; Ishikita, H. (2022). Correlation between C=O Stretching Vibrational Frequency and pKa Shift of Carboxylic Acids. The Journal of Physical Chemistry B, 126, 4999 - 5006. https://doi.org/10.1021/acs.jpcb.2c02193.\u003c/li\u003e\n \u003cli\u003eSmirnov, A. A., Khromova, S. A., Ermakov, D. Y., Bulavchenko, O. A., Saraev, A.\u003cbr\u003eA., Aleksandrov, P. V., et al. (2016). The Composition of Ni-Mo Phases\u003cbr\u003eObtained by NiMoOx-SiO2 Reduction and Their Catalytic Properties in\u003cbr\u003eAnisole Hydrogenation. Applied Catalysis A: General 514, 224\u0026ndash;234. doi:10.1016/j.\u003cbr\u003eapcata.2016.01.025\u003c/li\u003e\n \u003cli\u003eSuhaimia, H., Adama, A., Mrwana, A., Abdullaha, Z., Fahmi, M. O., Kamaruzzamana, M., \u0026amp; Hagosb, F. (2018). Analysis of combustion characteristics, engine performances and emissions of long-chain alcohol-diesel fuel blends. Fuel, 220, 682-691. https://doi.org/10.1016/J.FUEL.2018.02.019.\u003c/li\u003e\n \u003cli\u003eVandevyvere T., Sabbe M.K., Bouriakova A., Saravanamurugan S., Thybaut J.W., Lauwaert J. (2023). Impact of the incipient wetness impregnation sequence during the preparation of La or Ce promoted NiCu-Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e on low-temperature hydrodeoxygenation. Catalysis Communications, 181, 106734.\u003c/li\u003e\n \u003cli\u003eWang, Y., Su, Z., Duan, M., Fan, H., Ju, S., \u0026amp; Yang, C. (2024). Insights into the coupling of H2S adsorption and subsequent C4H4S hydrogenation over Ni\u0026ndash;Mo composite adsorbents. Chemical Engineering Science. https://doi.org/10.1016/j.ces.2024.120707.\u003c/li\u003e\n \u003cli\u003eWu Y., Xu X., Fan X., Sun Y., Tu R., Jiang E., Xu Q., Xu C.C. (2025). Catalytic Hydrodeoxygenation of Pyrolysis Volatiles from Pine Nut Shell over Ni-V Bimetallic Catalysts Supported on Zeolites. Catalysts, 15, 498. https://doi.org/10.3390/ catal15050498\u003c/li\u003e\n \u003cli\u003eXue X., Liu J., Xia D., Liang J. (2023). Hydrocarbon-rich bio-oil production from the coupling formaldehyde-pretreatment and catalytic pyrolysis of poplar sawdust. Biomass Bioenergy, 173, 106807.\u003c/li\u003e\n \u003cli\u003eYan P., Mensah J., Drewery M., Kennedy E., Maschmeyer T., Stockenhuber M. (2021). Role of metal support during ru-catalysed hydrodeoxygenation of biocrude oil. Applied Catalysis B Environmental, 281, 119470.\u003c/li\u003e\n \u003cli\u003eZhang W., Wang F., Feng J., Pan H. (2025). Effiient hydrodeoxygenation of guaiacol to cyclohexanol over Ni\u0026ndash;Co bimetallic nanoparticles supported on Al2O3\u0026ndash;TiOx. Biomass Bioenergy, 197,107841.\u003c/li\u003e\n \u003cli\u003eZhao S., Wang K. (2023). Regulation of the Reaction Route in Hydrogenation of\u003cbr\u003eRenewable Palm Oil Using NiMo Bimetallic Catalyst, Energy Fuel 37 (23),18899\u0026ndash;18910, https://doi.org/10.1021/acs.energyfuels.3c02598.\u003c/li\u003e\n \u003cli\u003eZhu, H., Dong, S., Xiong, J., Wan, P., Jin, X., Lu, S., Zhang, Y., \u0026amp; Fan, H. (2023). MOF derived cobalt-nickel bimetallic phosphide (CoNiP) modified separator to enhance the polysulfide adsorption-catalysis for superior lithium-sulfur batteries.. Journal of colloid and interface science, 641, 942-949 . https://doi.org/10.1016/j.jcis.2023.03.083.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Pyrolysis, catalyst, deoxygenation, hydrogenation, metal-loading ","lastPublishedDoi":"10.21203/rs.3.rs-7523942/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7523942/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cem\u003eThe high cost of post-pyrolysis upgrading of pyrolysis bio-oil due to its high oxygen and sulphur contents poses severe drawbacks to its use. This study investigates the influence of the Ni/Mo weight ratio and La loading on yield, deoxygenation, and desulfurization of bio-oil during in-situ catalytic pyrolysis of rice bran. The pyrolysis was performed at 450\u0026deg;C in a fixed bed reactor, using the catalysts synthesised via the sequential incipient wetness impregnation and calcination, with La loadings varied between 1\u0026ndash;3 wt%, Ni between 2\u0026ndash;10 wt%, and Mo between 2\u0026ndash;10 wt% to identify the most effective compositions. A mesoporous catalyst with a surface area of 205.45 m\u0026sup2;/g achieved a maximum bio-oil yield of 28.23% at a 1:1 Ni/Mo weight ratio with 1 wt% La. The low La concentration provides the balanced acidity and metal dispersion, promoting Ni hydrogenation potential and the cracking ability of Mo. A balanced Ni/Mo weight ratio also favoured sulphur removal due to the synergy of Ni promoting C\u0026ndash;S bond cleavage and Mo facilitating sulphur adsorption. Furthermore\u003c/em\u003e, \u003cem\u003ehigher Mo content loading produced enhanced sulphur reduction due to the availability of more Mo sites for sulphur adsorption. At a 2:1 Ni/Mo weight ratio with 2 wt% La loading, La regulates acidity and enhances metal dispersion to boost Ni-driven hydrogenation, while Mo stabilises Ni active sites, achieving 89% bio-oil deoxygenation. The bio-oil exhibits diesel-range properties with higher energy value and predominant long-chain hydrocarbons. The in-situ catalytic reaction enhanced cracking and decarboxylation, which reduces the oil's oxygen and sulphur contents at the source, thus reducing the complexity and post-pyrolysis upgrading cost.\u003c/em\u003e\u003c/p\u003e","manuscriptTitle":"Influence of Ni/Mo Ratio and Lanthanum Loading on Clay-Supported Ni–Mo Catalysts for In-Situ Rice Bran Pyrolysis: Optimizing Bio-Oil Yield, Deoxygenation, and Desulfurization","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-18 12:48:11","doi":"10.21203/rs.3.rs-7523942/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"abf79eb3-06dc-4fd1-876f-91ec6a657d2e","owner":[],"postedDate":"September 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-26T15:25:48+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-18 12:48:11","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7523942","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7523942","identity":"rs-7523942","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}