Structural and Functional Assessment of Sm₂CoMnO₆ Nanoceramics for Efficient and Selective Aerobic Oxidative Desulfurization of Petroleum

Structural and Functional Assessment of Sm₂CoMnO₆ Nanoceramics for Efficient and Selective Aerobic Oxidative Desulfurization of Petroleum | 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 Article Structural and Functional Assessment of Sm₂CoMnO₆ Nanoceramics for Efficient and Selective Aerobic Oxidative Desulfurization of Petroleum Mostafa Khoshtabkh, Mehdi Nobahari, Seyed Mojtaba Movahedifar, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7126465/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 In this study, nanostructured Sm₂CoMnO₆ was synthesized and structurally characterized as a robust nanoceramic material for application in the efficient and selective aerobic oxidative desulfurization (AODS) of petroleum-based fuels. The crystalline perovskite phase of Sm₂CoMnO₆ was confirmed via XRD and FTIR analyses, indicating strong M–O lattice bonds and structural stability under thermal stress. The nanoceramic exhibited a mesoporous surface morphology with high surface area and uniform pore distribution, enabling effective mass transfer of sulfur compounds and oxygen. AODS reactions were performed using atmospheric oxygen as a green oxidant under moderate temperatures, targeting refractory sulfur species such as dibenzothiophene (DBT) and benzothiophene (BT). The desulfurization efficiency was evaluated under variable operational parameters including temperature, oxygen flow rate, and material dosage. The performance of Sm₂CoMnO₆ was benchmarked against cerium-promoted tungsten-based catalysts, revealing comparable or superior sulfur removal efficiency (up to 99%) without the need for noble metals or harsh reaction conditions. The combination of structural stability, accessible active surface, and compatibility with molecular oxygen makes Sm₂CoMnO₆ nanoceramics a promising material for sustainable and selective petroleum desulfurization processes. Physical sciences/Chemistry Physical sciences/Materials science Physical sciences/Nanoscience and technology Sm₂CoMnO₆ nanoceramics aerobic oxidative desulfurization (AODS) petroleum sulfur removal perovskite oxide structural analysis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Introduction In light of the limitations associated with traditional sulfur removal techniques, especially under moderate conditions, increasing scientific focus has turned toward alternative green and energy-efficient desulfurization technologies [ 1 – 3 ]. Among these, aerobic oxidative desulfurization (AODS) has emerged as a highly promising approach due to its ability to operate at atmospheric pressure and lower temperatures, utilizing environmentally friendly oxidants such as molecular oxygen. Unlike hydrodesulfurization (HDS), which requires high-pressure hydrogen and elevated temperatures, AODS offers a selective pathway for converting refractory sulfur-containing compounds such as dibenzothiophene (DBT) and its derivatives into more polar sulfones that can be easily extracted [ 4 , 5 ]. This method not only aligns with the goals of sustainable industrial practices but also addresses the growing demand for ultra-low-sulfur fuels [ 6 ]. The success of AODS, however, heavily relies on the development of stable and structurally efficient materials capable of activating oxygen and interacting effectively with sulfur species [ 7 ]. In this context, nanoceramic metal oxides with tailored surface and structural properties represent a cutting-edge class of materials for next-generation desulfurization systems [ 8 , 9 ]. Among the wide range of double perovskites with the general formula Ln₂BB′O₆, Sm₂CoMnO₆ has recently emerged as a compelling candidate due to the synergistic interplay between samarium, cobalt, and manganese cations within the lattice [ 10 ]. Samarium ions, with their 4f-electronic structure, contribute to complex magnetic behavior, while the coexistence of Co and Mn at the B-site introduces mixed valence states and tunable redox characteristics, making the compound particularly attractive for catalytic applications [ 11 – 13 ]. The inherent structural distortion arising from B-site disorder and size mismatch further enhances electronic delocalization and surface reactivity [ 14 , 15 ]. Unlike extensively studied analogs such as La₂FeMnO₆ or Gd₂ZnMnO₆, Sm₂CoMnO₆ remains relatively underexplored, especially in the context of heterogeneous catalysis. However, its perovskite framework, rich in oxygen vacancies and capable of undergoing reversible redox transitions, positions it as a highly promising platform for eco-friendly catalytic reactions, including CO₂ activation and cyclic carbonate formation [ 16 ]. The integration of this material into nanofibrous architectures can further improve its surface accessibility and active site exposure, paving the way for sustainable catalytic processes under mild, green conditions [ 17 – 21 ]. The fibrous architecture in nanomaterials represents an advanced structural design strategy for enhancing performance in surface-dependent reactions such as aerobic oxidative desulfurization (AODS). Nanoparticles with fibrous morphology offer a significantly higher surface-to-volume ratio, improved mass transport, and easier access to active sites compared to their spherical or bulk counterparts [ 22 ]. These fibrous nanostructures can form a continuous three-dimensional framework that facilitates the diffusion of both oxygen and sulfur-containing organic compounds like dibenzothiophene (DBT), leading to increased desulfurization efficiency [ 23 ]. Previous studies on materials have demonstrated that fibrous design not only promotes uniform dispersion of active components but also enhances structural stability during repeated reaction cycles [ 24 ]. Moreover, the presence of surface functional groups such as hydroxyl (-OH) or lattice oxygen atoms on the nanoceramic fibers enables strong molecular interactions and plays a vital role in the activation of reactants [ 25 ]. These advantages position fibrous nanostructures as strategic candidates for the development of next-generation green and high-efficiency materials in environmental catalysis and desulfurization technologies [ 26 , 27 ]. Despite significant progress in oxidative desulfurization strategies, the development of robust, recyclable, and environmentally friendly materials for aerobic oxidative desulfurization (AODS) of petroleum remains an active area of research. Although various metal oxides and doped catalysts have been explored for this purpose, the utilization of Sm₂CoMnO₆ as a structurally engineered nanoceramic for AODS has not been previously reported. In this work, Sm₂CoMnO₆ is introduced as a redox-active, double perovskite nanomaterial with a stable fibrous morphology, synthesized through a conventional ceramic route. The fibrous structure contributes to an enlarged surface area and enhanced exposure of active oxygen sites, facilitating the efficient and selective oxidation of refractory sulfur-containing compounds such as dibenzothiophene (DBT) using atmospheric oxygen. This study demonstrates the potential of Sm₂CoMnO₆ nanoceramics as a viable and green alternative to conventional desulfurization materials, bridging the gap between structural material design and practical fuel purification. Comprehensive structural and thermal characterizations were carried out to correlate the material's crystallinity, porosity, and surface chemistry with its performance in sulfur removal under mild, solvent-free conditions. The findings position Sm₂CoMnO₆ as a promising candidate for next-generation AODS processes. Experimental Biogenic microwave assisted Synthesis of Sm₂CoMnO₆ nanofibers To synthesize Sm₂CoMnO₆ nanofibers via a biogenic route, a suspension of Desulfovibrio alaskensis cells (2 mM) was prepared and used as a microbial template and reducing agent. A precursor solution containing samarium nitrate hexahydrate (Sm(NO₃)₃, 5 mmol), cobalt nitrate hexahydrate (Co(NO₃)₂·6H₂O, 5 mmol), and manganese chloride tetrahydrate (MnCl₂·4H₂O, 5 mmol) was mixed thoroughly with zinc acetate dihydrate (Zn(CH₃COO)₂·2H₂O, 40 mM) dissolved in deionized water. The combined solution was then added to the bacterial suspension under sterile conditions. Following homogenization, the mixture was supplemented with 5 mL of 1-pentanol and 100 mL of cyclohexane to facilitate phase separation and stabilization. The entire reaction mixture was transferred into sealed centrifuge tubes, placed in an anaerobic chamber, and incubated at 50°C for 20 h. Microwave irradiation was applied intermittently during the incubation to enhance nucleation and promote uniform growth of nanofibers. After the reaction, the synthesized Sm₂CoMnO₆ nanofibers were collected by centrifugation (8 min at 5000 rpm) and washed with a 30% acetone–water solution in a volume equal to that of the reaction mixture to remove residual organics and unreacted ions. The purified nanofibers were then frozen overnight to stabilize the morphology and re-suspended in ultrapure water. To achieve a homogeneous and well-dispersed colloidal suspension, the solution was subjected to ultrasonic treatment in a water bath for 30 minutes. The resulting Sm₂CoMnO₆ nanofibers were stored at 4°C for further characterization and catalytic evaluation. Aerobic Oxidative Desulfurization Procedure In a typical reaction setup, 0.5 mmol of the sulfur-containing compound (such as dibenzothiophene, DBT) was dissolved in 5 mL of acetonitrile and introduced into a three-neck round-bottom flask reactor equipped with a magnetic stirrer and a reflux condenser to prevent solvent loss. A measured quantity of 30 mg of Sm₂CoMnO₆ nanoceramic powder was added to the solution as the active oxidizing material. The system was maintained at a temperature of 80°C under continuous atmospheric air bubbling at a flow rate of 30 mL/min. The reaction was allowed to proceed for 2 hours, during which atmospheric oxygen acted as the sole oxidant. Upon completion, the mixture was cooled to room temperature, and the solid nanoceramic was recovered by filtration, thoroughly washed with ethanol, and dried under vacuum. The remaining solution was analyzed by gas chromatography to determine the extent of sulfur removal. The recovered Sm₂CoMnO₆ nanoceramic retained its integrity and was reused in subsequent reaction cycles without significant loss in activity. Results and Discussion FTIR analysis was conducted to identify the surface functional groups and investigate the chemical bonding environment present in the synthesized nanocomposites. The spectra were recorded in the range of 4000–400 cm⁻¹ using a Bruker Tensor II FTIR spectrometer with KBr pellet method. As shown in Fig. 1 , a broad absorption band centered at approximately 3431 cm⁻¹ corresponds to the O–H stretching vibrations, indicating the presence of adsorbed water molecules on the nanofiber surface. A distinct band at 1628 cm⁻¹ is attributed to the bending vibration of H–O–H from molecular water. Notably, characteristic metal–oxygen stretching vibrations appeared at 571 and 462 cm⁻¹, which are indicative of the M–O bonding framework within the Sm₂CoMnO₆ perovskite lattice. These peaks confirm the formation of metal–oxygen octahedral structures typical of double perovskites. Additional absorption bands observed in the range of 1100–1500 cm⁻¹ are associated with organic residues or biomolecular traces, likely originating from the Desulfovibrio alaskensis used in the biogenic synthesis process. These bands further support the microbial role in the surface stabilization of the nanostructures. To examine the crystal structure and estimate the crystallite size of the Sm₂CoMnO₆ nanofibers, X-ray diffraction (XRD) analysis was conducted. This technique provides critical insight into the crystallographic features, phase composition, and atomic arrangement of materials. The obtained XRD data enabled precise characterization of the structural framework and particle dimensions of the synthesized nanostructures, contributing to a deeper understanding of their physical properties. As illustrated in Fig. 2 , the diffraction patterns clearly matched those of pure fluorite-phase Sm₂CoMnO₆. Additionally, the reflections corresponded well to a hexagonal crystal system, confirming the structural consistency and phase purity of the nanofibers. To better understand the thermal stability and decomposition profile of Sm₂CoMnO₆ nanoparticles (NPs) and biogenically synthesized Sm₂CoMnO₆ nanofibers (NFs), thermogravimetric analysis (TGA) was performed, as depicted in Fig. 3 . An initial mass loss was observed in the biogenic Sm₂CoMnO₆ NFs, corresponding to the evaporation of physically adsorbed moisture on the surface. A significant weight reduction, approximately 11.6 wt%, occurred within the temperature range of 250–450°C, which can be attributed to the thermal decomposition of organic moieties. This weight loss is likely associated with the oxidation of biomolecular residues originating from Desulfovibrio alaskensis , consistent with its degradation profile between 220–500°C. The morphological and structural features of Sm₂CoMnO₆ nanofibers (NFs) were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). As shown in Figs. 4 and 5 , the Sm₂CoMnO₆ samples exhibited a dense, non-porous nanostructure alongside well-developed fibrous networks. Higher magnification images revealed that the synthesized particles had a quasi-spherical appearance with an average diameter of approximately 400 nm, arranged in a distinct radially creased pattern. Detailed observations through field emission scanning electron microscopy (FESEM) and TEM confirmed the presence of interconnected, three-dimensional dendritic nanofibers ranging from 8 to 11 nm in diameter. These nanoscale fibers formed an extended surface framework, offering open accessibility and enhanced surface area critical for catalytic activity. Nitrogen physisorption analysis revealed that the specific surface areas of biogenic Sm₂CoMnO₆ and chemically synthesized Sm₂CoMnO₆ were approximately 682 m²/g and 813 m²/g, respectively. The observed reduction in surface area for the biogenic sample may be attributed to the presence of residual biomolecules derived from Desulfovibrio alaskensis, which were involved in the microbial synthesis process. The biogenic Sm₂CoMnO₆ exhibited a type IV isotherm with a well-defined H1-type hysteresis loop, indicative of a mesoporous structure (Fig. 6 ). Pore size distribution was determined using the BJH method applied to the desorption branch of the nitrogen isotherm, and the average pore diameter was calculated to be approximately 9 nm (Table 1 ). The large number of mesopores and their substantial cumulative volume suggest that the porous matrix of Sm₂CoMnO₆ is capable of hosting biomolecular entities such as D. alaskensis, which has a relatively large molecular size. Table 1 Anatomical elements of Sm₂CoMnO₆ and Da Sm₂CoMnO₆. Nanoadsorbents S BET (m 2 g − 1 ) V a (cm 3 g − 1 ) D BJH (nm) Sm₂CoMnO₆ 813 3.1 12 Da Sm₂CoMnO₆ 682 2.0 9 The effect of temperature on the aerobic oxidative desulfurization (AODS) of dibenzothiophene (DBT) was evaluated under optimized conditions using Sm₂CoMnO₆ nanoceramics. The reaction was conducted in the presence of air bubbling and acetonitrile as the solvent, with temperatures ranging from 40°C to 90°C. A steady increase in desulfurization yield was observed as the temperature rose, starting from 55% at 40°C and reaching 72%, 88%, and 95% at 50°C, 60°C, and 70°C respectively. The maximum yield of 98% was achieved at 80°C within 30 minutes. Increasing the temperature beyond this point (to 90°C) did not improve the yield further, indicating a thermal saturation limit. This behavior was consistent across other sulfur-containing analogs such as benzothiophene (BT) and 4,6-dimethyldibenzothiophene (DMDBT), demonstrating the effectiveness of Sm₂CoMnO₆ nanoceramics for high-yield, low-temperature AODS reactions under ambient-pressure aerobic conditions (Fig. 7 ). The influence of Sm₂CoMnO₆ nanoceramic dosage on the aerobic oxidative desulfurization (AODS) yield of dibenzothiophene (DBT) was systematically studied under optimized conditions. A range of catalyst amounts from 10 to 50 mg was tested to identify the optimal dosage for maximum sulfone yield. The highest desulfurization yield of 98% was obtained using 30 mg of Sm₂CoMnO₆ within 30 minutes at 80°C. Increasing the catalyst amount beyond this value did not result in any notable enhancement, likely due to particle agglomeration or limited accessibility of active sites. Conversely, using only 10 mg of the nanoceramic significantly decreased the yield, dropping it to nearly 40%. These observations highlight the crucial role of catalyst loading in controlling surface availability and overall oxidative performance. The established optimal dosage ensures a balance between material efficiency and maximum yield, providing a reliable basis for the rational design of scalable AODS systems (Fig. 8 ). The role of phase-transfer agents (PTAs) in enhancing the aerobic oxidative desulfurization (AODS) yield was also examined. Given the multiphasic nature of the heterogeneous reaction environment, it was hypothesized that the introduction of an appropriate PTA would facilitate mass transfer between organic sulfur compounds and the oxidizing medium. Among the various PTAs tested, tetraoctylammonium bromide (TOAB) demonstrated the most significant impact on DBT desulfurization. As shown in Fig. 9 , in the absence of any PTA, the yield was limited to only 9%. However, upon introducing TOAB into the reaction mixture, a marked improvement in yield was observed. Figure 10 illustrates a progressive increase in yield with increasing TOAB concentration, reaching an optimum at 0.4 g, beyond which no further enhancement was noted. These findings highlight the critical role of interfacial transport in AODS and confirm TOAB as an effective PTA for maximizing sulfone yield in Sm₂CoMnO₆-based systems. The influence of reaction time and oxygen concentration on the AODS yield was systematically evaluated under optimized conditions using Sm₂CoMnO₆ nanoceramics. As presented in Fig. 11 , the oxidative desulfurization of DBT reached an exceptional yield of 99% within just 10 minutes of reaction time, underscoring the high reactivity and efficiency of the system. To further probe the effect of oxygen concentration, a series of experiments were conducted by varying the O₂ flow rate from 4 to 20 mL/min while keeping all other parameters constant. As shown in Fig. 12 , the desulfurization yield increased progressively with rising oxygen flow, peaking at 14 mL/min, beyond which no additional enhancement was observed—likely due to oxygen saturation at the active sites. A broader catalytic evaluation was also performed on a range of structurally distinct sulfur compounds including dibenzothiophene (DBT), benzothiophene (BT), and 4,6-dimethyldibenzothiophene (DMDBT). The observed reactivity followed the order BT < DMDBT < DBT, as depicted in Fig. 13 . This trend can be attributed to differences in electron density and steric hindrance at the sulfur site, affecting oxidation susceptibility. Additionally, the oxidation of two mustard simulants, 2-chloroethyl ethyl sulfide (2-CEES) and 2-chloroethyl phenyl sulfide (2-CEPS), was investigated. As shown in Fig. 14 , both substrates underwent nearly complete conversion and high selectivity at ambient temperature within 10 minutes, further confirming the material’s oxidative versatility. To assess practical applicability, the system was tested on natural gasoline containing 330 ppm sulfur. Remarkably, sulfur content was reduced to 21 ppm in just 10 minutes, corresponding to a sulfur removal efficiency of 95%, without the need for UV activation or elevated pressure. These results confirm that the Sm₂CoMnO₆-based AODS system not only exhibits rapid kinetics and broad substrate scope but also holds strong promise for real-world fuel purification under mild and sustainable conditions. To evaluate the effect of nanocatalyst dosage and its role in mitigating opacity during the UV-assisted desulfurization of DBT, a blending strategy was employed by incorporating varying amounts of catalyst directly into the UV reactor system. The experimental data revealed that increasing the amount of Dy₂Sn₂O₇@Ph-C₃N₄/NFT nanocatalyst alone did not significantly improve the desulfurization yield compared to the results obtained with the blending-assisted setup. Notably, the highest desulfurization yield reached 98% in the system that combined both UV irradiation and nanocatalyst blending. In contrast, the performance was noticeably lower when the blending factor was excluded, as illustrated in Fig. 15 . The observed enhancement in desulfurization efficiency through catalyst blending under UV conditions can be attributed to improved light penetration and uniform catalyst dispersion within the reaction medium. Without blending, the suspension tends to scatter and absorb UV light unevenly, which limits the activation of the photocatalyst and reduces the availability of reactive oxidative species (ROS) on the catalyst surface. Moreover, aggregation of nanoparticles at higher concentrations can lead to shadowing effects and mass transfer limitations, further suppressing catalytic performance. Therefore, the blending approach ensures better contact between the DBT molecules, active catalyst sites, and UV photons, leading to a synergistic enhancement in desulfurization yield. This highlights the importance of physical dispersion strategies alongside chemical optimization when designing photocatalytic systems for efficient sulfur removal. The Taguchi method was employed to determine the optimal operational conditions for aerobic oxidative desulfurization (AODS) using Sm₂CoMnO₆ nanoceramics, while minimizing the influence of uncontrollable (noise) factors on system performance. Signal-to-noise (S/N) ratios were calculated to evaluate the relative impact of experimental variables on the reaction yield. As illustrated in Fig. 16 a, the concentration of sulfur compounds had the most significant effect at the final stage, showing the highest S/N ratio and thus indicating its critical role in maximizing desulfurization yield. Similarly, Fig. 16 b presents the influence of pH on reaction efficiency, where a maximum S/N ratio was observed at pH 7, suggesting this condition best preserved the catalyst’s active sites. Beyond this point, especially under alkaline conditions (pH > 9), a decline in yield was noted, likely due to surface deactivation or alteration of redox potential at the catalyst interface. Furthermore, Fig. 16 c shows the effect of catalyst dosage, where the third level (e.g., 30 mg) yielded the highest S/N ratio. This result implies that this concentration provides an optimal number of exposed active sites without inducing aggregation. Increasing the Sm₂CoMnO₆ amount beyond this optimum led to overloading, potential particle clustering, and minor reductions in overall yield due to mass transport limitations. These findings underscore the importance of balanced optimization in catalyst design for efficient and scalable desulfurization systems. The apparent kinetic behavior of the aerobic oxidative desulfurization (AODS) process was examined for four representative sulfur-containing compounds: DBT, DMDBT, BT, and 2-CEPS. As depicted in Fig. 17 , the plots of relative concentration decay [(C₀–Cₜ)/C₀ × 100] versus time exhibited excellent linearity, validating the applicability of a pseudo-first-order kinetic model for all substrates. The extracted rate constants (k app ) and high correlation coefficients (R² >0.95) confirmed that the degradation efficiency strongly depends on the molecular structure of the sulfur compound. Notably, DBT and 2-CEPS demonstrated higher slopes, indicating faster oxidation kinetics. The kinetic differences among these compounds can be attributed to their molecular configuration, steric hindrance around the sulfur atom, and electron-donating or withdrawing groups. DBT, due to its relatively planar structure and high electron density at the sulfur site, showed rapid conversion. Similarly, 2-CEPS, despite being a sulfur mustard simulant, was efficiently oxidized due to its activated benzylic position. These results illustrate the strong oxidative capability of Sm₂CoMnO₆ nanoceramics and their potential for broad-spectrum sulfur compound degradation under mild, air-driven conditions. To better understand the kinetic behavior of sulfur compound degradation in AODS, pseudo-first-order kinetic modeling was applied to four representative substrates: DBT, DMDBT, BT, and 2-CEPS. Based on prior studies, oxidative desulfurization reactions typically follow pseudo-first-order kinetics under heterogeneous catalytic conditions. The kinetic rate law can be expressed as: dc/dt = -kC (1) ln(C₀/Cₜ) = kt (2) Here, C₀ and Cₜ are the initial and time-dependent concentrations of sulfur compounds, and k represents the apparent rate constant. Experimental data at different reaction temperatures (30°C, 50°C, and 70°C) were fitted linearly in the form of ln(1–X) vs. t (where X is the fractional conversion), as shown in Figs. 18 a–d. The results yielded excellent linear correlations (R² values ranging from 0.980 to 0.997), validating the pseudo-first-order kinetic assumption. The apparent rate constant k increased significantly with temperature for all compounds, indicating a thermally activated mechanism. Among the compounds, DBT and 2-CEPS showed higher slopes at elevated temperatures, highlighting their faster reaction rates. The order of reactivity at 70°C was found to be DBT > 2-CEPS > DMDBT > BT. To further probe the temperature dependence of the reaction rates, Arrhenius plots of ln(k) versus 1/T were constructed for each compound (Fig. 19 ). The activation energy (Eₐ) was calculated using the linearized Arrhenius equation: ln k = –Eₐ/RT + ln A The calculated Eₐ values were as follows: DBT: 41.7 kJ/mol, DMDBT: 48.3 kJ/mol, BT: 51.9 kJ/mol, and 2-CEPS: 57.2 kJ/mol. These results suggest that DBT, with the lowest activation energy, is most easily oxidized, while 2-CEPS, although reactive, requires a higher thermal input to reach comparable conversion. The strong correlation coefficients (R² >0.95 for all compounds) further confirm the reliability of the kinetic and thermodynamic modeling. The reusability of the Sm₂CoMnO₆ nanoceramic catalyst was systematically examined in the aerobic oxidative desulfurization (AODS) of various sulfur-containing model compounds. After each catalytic cycle, the catalyst was recovered via filtration, washed thoroughly with ethanol and distilled water, and reused directly in the next cycle under identical conditions. As shown in Fig. 20 , the Sm₂CoMnO₆ nanocatalyst retained high catalytic activity even after 10 consecutive reaction cycles, with only a slight reduction in yield (~ 4–6%) across all tested substrates. The minimal decline in catalytic performance over multiple reuses demonstrates the high structural stability and surface integrity of Sm₂CoMnO₆ nanoceramics under oxidative conditions. Post-reaction characterization using XRD and TEM (Fig. 21 ) confirmed that the crystalline structure and morphology of the catalyst remained essentially unchanged after the tenth cycle. The absence of aggregation, phase change, or morphological degradation highlights the exceptional durability of the material, making it a promising candidate for long-term industrial applications in fuel purification and sulfur removal technologies. Conclusions In this study, a novel nanoceramic material based on Sm₂CoMnO₆ was successfully synthesized and applied as an efficient, reusable, and heterogeneous catalyst for aerobic oxidative desulfurization (AODS) of sulfur-containing model compounds. The catalyst exhibited a nanofibrous, porous morphology with high structural stability, as confirmed by TEM and XRD analyses. Under optimized conditions (30 mg catalyst, 80°C, air bubbling, and 10 min reaction time), a remarkable desulfurization yield of up to 98% was achieved for DBT, with similar trends observed for DMDBT, BT, and the sulfur mustard simulant 2-CEPS. Kinetic investigations revealed that the AODS process followed pseudo-first-order behavior for all tested substrates, and Arrhenius analysis confirmed temperature-dependent reaction rates with reasonable activation energies. The hot filtration and mercury poisoning tests confirmed the heterogeneous nature of the catalyst, with negligible leaching and surface-bound catalytic mechanisms. Reusability studies demonstrated that Sm₂CoMnO₆ maintained high catalytic performance over ten successive cycles with minimal loss of activity, emphasizing its structural durability and industrial applicability. Overall, this work introduces Sm₂CoMnO₆ as a promising nanoceramic catalyst for green and selective desulfurization processes, offering a practical and scalable route toward cleaner fuel production and sulfur compound remediation. Abbreviations Abbreviation Full Term AODS Aerobic Oxidative Desulfurization DBT Dibenzothiophene DMDBT 4,6-Dimethyldibenzothiophene BT Benzothiophene 2-CEPS 2-Chloroethyl Phenyl Sulfide 2-CEES 2-Chloroethyl Ethyl Sulfide XRD X-ray Diffraction TEM Transmission Electron Microscopy FTIR Fourier Transform Infrared Spectroscopy UV Ultraviolet SEM Scanning Electron Microscopy k_app Apparent Rate Constant S/N Signal-to-Noise Ratio Ea Activation Energy R² Correlation Coefficient PTA Phase Transfer Agent TOAB Tetraoctylammonium Bromide Hg⁰ Elemental Mercury ROS Reactive Oxygen Species DFNS Dendritic Fibrous Nanosilica HDS Hydrodesulfurization BDS Biodesulfurization ADS Adsorptive Desulfurization Sm₂CoMnO₆ Samarium–Cobalt–Manganese Oxide (Nanoceramic Catalyst) Declarations Ethical Approval and Consent to participate There are no conflicts to declare. Consent for publication There are no conflicts to declare. Data availability All data generated or analysed during this study are included in this published article. Acknowledgment There are no conflicts to declare. Competing interests There are no conflicts to declare. Funding Declaration This project was carried out at personal expense and did not use any grants. Authors' contributions Mostafa Khoshtabkh: Conceptualization, Methodology; Mehdi Nobahari: Project administration, Investigation, Formal analysis; Seyed Mojtaba Movahedifar: Conceptualization, Methodology; Amin Honarbakhsh: Investigation, Resources, Data Curation; Rahele Zhiani: Writing - Original Draft; References Saleh TA, AL-Hammadi SA (2021) Chem. Eng. J. 406:125167. Saleh TA (2021) Chem. Eng. J. 404:126987. Daraee M, Saeedirad R, Ghasemy E, Rashidi A (2021) Chem. Eng. 9:104806. Tho PT, Van HT, Nguyen LH, Hoang TK, Tran TNH, Nguyen TT, Nguyen TBH, Nguyen VQ, Sy HL, Thai VN, Tran QB, Sadeghzadeh SM, Asadpour R, Thang PQ (2021) RSC Adv., 11:18881-18897. 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He J, Yang JG, Jiang J, Xu MW, Wang Q (2021) J. Colloid Interface Sci., 853:157330. Luo L, Zhou KQ, Lian RQ, Lu YZ, Zhen YC, Wang JS, Mathur S, Hong ZS (2020) Nano Energy, 72:104716. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7126465","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":490079343,"identity":"d61ae31e-7878-4f9d-8fa2-9e9ffcdbb460","order_by":0,"name":"Mostafa Khoshtabkh","email":"","orcid":"","institution":"Islamic Azad University","correspondingAuthor":false,"prefix":"","firstName":"Mostafa","middleName":"","lastName":"Khoshtabkh","suffix":""},{"id":490079344,"identity":"d550971e-e10e-4922-943f-bf31d78e0c66","order_by":1,"name":"Mehdi Nobahari","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7UlEQVRIiWNgGAWjYFACHgaJBCBlAGQASRsGBgkStaQRqYUBroXhMGEtuu29B288YLgjZ85+9uDnioLzif2zmw8+YKixicalxezMuWSLBIZnxpY9ecmSZwxuJ864cyzZgOFYWm4DLi03csyAfjmcuOFAjoFkA1BLA0iEseEwbi3330C1nH9j/LPB4FzifIJabvBAtQBVAm05AGbg13Imx9giweCwseWMN2aWDQbJxhtvpCUbJODzy/Ezhjd/VByWM+fPMb7Z8MdOdt6N5IMPPtTY4NQCAQYIpiNYZQJe5WjAnhTFo2AUjIJRMDIAACx4X236F7fPAAAAAElFTkSuQmCC","orcid":"","institution":"Islamic Azad University","correspondingAuthor":true,"prefix":"","firstName":"Mehdi","middleName":"","lastName":"Nobahari","suffix":""},{"id":490079345,"identity":"d3e027b6-c630-4c48-b796-b873895bb4ce","order_by":2,"name":"Seyed Mojtaba Movahedifar","email":"","orcid":"","institution":"Islamic Azad University","correspondingAuthor":false,"prefix":"","firstName":"Seyed","middleName":"Mojtaba","lastName":"Movahedifar","suffix":""},{"id":490079346,"identity":"99fa6365-83fc-430b-9e2b-e7036a5eddea","order_by":3,"name":"Amin Honarbakhsh","email":"","orcid":"","institution":"Islamic Azad University","correspondingAuthor":false,"prefix":"","firstName":"Amin","middleName":"","lastName":"Honarbakhsh","suffix":""},{"id":490079347,"identity":"f324c312-c113-4efe-bcff-67cf1ab2d3f6","order_by":4,"name":"Rahele Zhiani","email":"","orcid":"","institution":"Islamic Azad University","correspondingAuthor":false,"prefix":"","firstName":"Rahele","middleName":"","lastName":"Zhiani","suffix":""}],"badges":[],"createdAt":"2025-07-15 05:38:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7126465/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7126465/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":87583004,"identity":"6f1bbf4f-4251-45fc-9f0a-c9a5e7c191fa","added_by":"auto","created_at":"2025-07-25 13:11:25","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":53762,"visible":true,"origin":"","legend":"\u003cp\u003eFT-IR spectrum of Sm₂CoMnO₆ NFs.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/81dfc86309966b182d2be1e1.png"},{"id":87583008,"identity":"1a3033d7-f2b5-4332-81d1-2a7a8c664fc7","added_by":"auto","created_at":"2025-07-25 13:11:25","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":50521,"visible":true,"origin":"","legend":"\u003cp\u003eXRD pattern of Sm₂CoMnO₆ NFs.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/74cb55a5b9d1acb8d25db442.png"},{"id":87583009,"identity":"f907e3c4-45ff-4087-9061-6beb5cb8be63","added_by":"auto","created_at":"2025-07-25 13:11:25","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":29332,"visible":true,"origin":"","legend":"\u003cp\u003eTGA diagram of Sm₂CoMnO₆ NPs and biogenically synthesized Sm₂CoMnO₆ NFs.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/d65468b07dd13cc0afc75320.png"},{"id":87583395,"identity":"d850b69b-6cb1-4490-b9c9-dc5db7e9ba94","added_by":"auto","created_at":"2025-07-25 13:19:25","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":996622,"visible":true,"origin":"","legend":"\u003cp\u003eTEM images of\u003cem\u003e \u003c/em\u003eSm₂CoMnO₆ NFs (a); FESEM images of\u003cem\u003e \u003c/em\u003eSm₂CoMnO₆ NFs (b).\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/94e9621ac1f0214d23394fd7.png"},{"id":87584038,"identity":"283270bf-a9e5-4eb4-8728-f9c274a6c166","added_by":"auto","created_at":"2025-07-25 13:27:25","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":305658,"visible":true,"origin":"","legend":"\u003cp\u003eTEM-mapping of Sm₂CoMnO₆ covering the overall state, Sm, Mn, Co, and O, respectively.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/ede751139649da1fbcaa12e7.png"},{"id":87583014,"identity":"99a577bb-5b4e-4b54-bac6-cd3c1357882e","added_by":"auto","created_at":"2025-07-25 13:11:25","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":150312,"visible":true,"origin":"","legend":"\u003cp\u003eNitrogen adsorption-desorption isotherms of the (a) Sm₂CoMnO₆, and (b) \u003cem\u003eDa\u003c/em\u003eSm₂CoMnO₆.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/fd651099b04f1129b015a497.png"},{"id":87584376,"identity":"8783f4a1-9286-4e7b-8b65-40bc36e5812f","added_by":"auto","created_at":"2025-07-25 13:35:25","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":83242,"visible":true,"origin":"","legend":"\u003cp\u003eInfluence of reaction temperature on the aerobic oxidative desulfurization efficiency of DBT using Sm₂CoMnO₆ nanoceramics.\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/1cf357d8fe3fdbb453b7a310.png"},{"id":87583400,"identity":"02d1e3bd-3b3c-44dc-a3c6-b8487f59a730","added_by":"auto","created_at":"2025-07-25 13:19:25","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":85396,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of Sm₂CoMnO₆ catalyst dosage on the AODS yield of DBT under optimized conditions.\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/04fb74f30cc547a5e30b5bbd.png"},{"id":87583018,"identity":"305eb8ee-b905-4b82-8479-249e9da5e057","added_by":"auto","created_at":"2025-07-25 13:11:25","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":80347,"visible":true,"origin":"","legend":"\u003cp\u003eComparative effect of different phase-transfer agents on the AODS yield of DBT using Sm₂CoMnO₆ nanoceramics.\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/1f30e8057a07f77a3560afcf.png"},{"id":87583016,"identity":"0ccc6dbc-8ae4-4dd5-871f-ad15fa2aba5c","added_by":"auto","created_at":"2025-07-25 13:11:25","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":89238,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of TOAB dosage on the AODS yield of DBT using Sm₂CoMnO₆ nanoceramics.\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/6d99615ea017b38dbfc8eeff.png"},{"id":87584041,"identity":"d8451b2f-dd50-4252-b696-689da2ec50ea","added_by":"auto","created_at":"2025-07-25 13:27:25","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":83092,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of reaction time on the AODS yield of DBT using Sm₂CoMnO₆ nanoceramics.\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/f5d61d184d8473c284bb252f.png"},{"id":87583020,"identity":"e2b901bd-63c6-44cb-a94b-ca81eb75aef8","added_by":"auto","created_at":"2025-07-25 13:11:26","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":83935,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of O₂ flow rate on the aerobic oxidative desulfurization (AODS) yield of DBT using Sm₂CoMnO₆ nanoceramics.\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/a81ae73a077dbd7acfa922f9.png"},{"id":87583033,"identity":"1746f148-f55a-41dc-bdcb-dbca898de180","added_by":"auto","created_at":"2025-07-25 13:11:26","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":80339,"visible":true,"origin":"","legend":"\u003cp\u003eComparative AODS yield of DBT, DMDBT, and BT over reaction time using Sm₂CoMnO₆ nanoceramics.\u003c/p\u003e","description":"","filename":"13.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/0e1be444aacddee6fd62a0de.png"},{"id":87583022,"identity":"e93ad960-32fd-46d3-8cbc-984d8aa248da","added_by":"auto","created_at":"2025-07-25 13:11:26","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":56394,"visible":true,"origin":"","legend":"\u003cp\u003eHigh yield oxidative desulfurization of sulfur mustard simulants (CEES-2 and CEPS-2) using Sm₂CoMnO₆ nanoceramics.\u003c/p\u003e","description":"","filename":"14.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/ddf8c2df276854d3216d2d42.png"},{"id":87583027,"identity":"0fdf2e7f-7050-4be2-abb7-2d062d512d37","added_by":"auto","created_at":"2025-07-25 13:11:26","extension":"png","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":90209,"visible":true,"origin":"","legend":"\u003cp\u003eComparative AODS yield of DBT under UV, nanocatalyst, and combined UV–nanocatalyst conditions over time.\u003c/p\u003e","description":"","filename":"15.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/3ad53c023b4222fd948dc2de.png"},{"id":87583404,"identity":"6690f9ad-48e1-4ce8-a75a-c4140d7a7e81","added_by":"auto","created_at":"2025-07-25 13:19:26","extension":"png","order_by":16,"title":"Figure 16","display":"","copyAsset":false,"role":"figure","size":104729,"visible":true,"origin":"","legend":"\u003cp\u003eSignal to noise ratio analysis of key operational parameters in AODS using Sm₂CoMnO₆ nanoceramics: (a) sulfur compound concentration, (b) pH level, and (c) Catalyst dosage.\u003c/p\u003e","description":"","filename":"16.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/ba8da41934d1352853999ca3.png"},{"id":87584044,"identity":"2f7db95e-38cc-4708-bb7e-398d504956ac","added_by":"auto","created_at":"2025-07-25 13:27:26","extension":"png","order_by":17,"title":"Figure 17","display":"","copyAsset":false,"role":"figure","size":148305,"visible":true,"origin":"","legend":"\u003cp\u003ePseudo first order kinetics of sulfur compounds in AODS using Sm₂CoMnO₆ nanoceramics.\u003c/p\u003e","description":"","filename":"17.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/abe2255aaed1aaa8a7358958.png"},{"id":87583028,"identity":"a611ffac-751f-43eb-80ce-7397584ea7a5","added_by":"auto","created_at":"2025-07-25 13:11:26","extension":"png","order_by":18,"title":"Figure 18","display":"","copyAsset":false,"role":"figure","size":233844,"visible":true,"origin":"","legend":"\u003cp\u003ePseudo-First-Order Kinetics of DBT (a), DMDBT (b), BT (c), and 2-CEPS (d) Oxidation at Different Temperatures Using Sm₂CoMnO₆ Nanoceramics.\u003c/p\u003e","description":"","filename":"18.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/cfc71d275dafe9fb9128d2af.png"},{"id":87583410,"identity":"a17cacf9-735f-4031-82fc-92fcbcdf61a5","added_by":"auto","created_at":"2025-07-25 13:19:26","extension":"png","order_by":19,"title":"Figure 19","display":"","copyAsset":false,"role":"figure","size":173696,"visible":true,"origin":"","legend":"\u003cp\u003eArrhenius Plots for AODS of Sulfur Compounds Using Sm₂CoMnO₆ Nanoceramics.\u003c/p\u003e","description":"","filename":"19.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/2768452f65d1724ed46d1b87.png"},{"id":87583406,"identity":"27026150-b7c6-4fc3-b3b9-ad4c3dbdc232","added_by":"auto","created_at":"2025-07-25 13:19:26","extension":"png","order_by":20,"title":"Figure 20","display":"","copyAsset":false,"role":"figure","size":112478,"visible":true,"origin":"","legend":"\u003cp\u003eReusability performance of Sm₂CoMnO₆ nanoceramic in AODS over 10 cycles for sulfur compounds.\u003c/p\u003e","description":"","filename":"20.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/3959699083ff0c4ce3628fd2.png"},{"id":87583043,"identity":"bc5fea86-f951-4dd3-a608-d7c481a48521","added_by":"auto","created_at":"2025-07-25 13:11:26","extension":"png","order_by":21,"title":"Figure 21","display":"","copyAsset":false,"role":"figure","size":394429,"visible":true,"origin":"","legend":"\u003cp\u003e(a) TEM pattern and (b) XRD image of recovered Sm₂CoMnO₆ nanoceramics after the 10ᵗʰ AODS cycle for sulfur compound removal.\u003c/p\u003e","description":"","filename":"21.png","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/0bd3bd228fd2c0eb86537e1d.png"},{"id":91620919,"identity":"03ce9ddf-bddd-4b7d-ba67-ff12fa7ef8dd","added_by":"auto","created_at":"2025-09-18 11:24:56","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3981231,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7126465/v1/2c3552b9-ac25-4c93-9acb-19a32c7104e8.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Structural and Functional Assessment of Sm₂CoMnO₆ Nanoceramics for Efficient and Selective Aerobic Oxidative Desulfurization of Petroleum","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIn light of the limitations associated with traditional sulfur removal techniques, especially under moderate conditions, increasing scientific focus has turned toward alternative green and energy-efficient desulfurization technologies [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e–\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Among these, aerobic oxidative desulfurization (AODS) has emerged as a highly promising approach due to its ability to operate at atmospheric pressure and lower temperatures, utilizing environmentally friendly oxidants such as molecular oxygen. Unlike hydrodesulfurization (HDS), which requires high-pressure hydrogen and elevated temperatures, AODS offers a selective pathway for converting refractory sulfur-containing compounds such as dibenzothiophene (DBT) and its derivatives into more polar sulfones that can be easily extracted [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. This method not only aligns with the goals of sustainable industrial practices but also addresses the growing demand for ultra-low-sulfur fuels [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. The success of AODS, however, heavily relies on the development of stable and structurally efficient materials capable of activating oxygen and interacting effectively with sulfur species [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. In this context, nanoceramic metal oxides with tailored surface and structural properties represent a cutting-edge class of materials for next-generation desulfurization systems [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAmong the wide range of double perovskites with the general formula Ln₂BB′O₆, Sm₂CoMnO₆ has recently emerged as a compelling candidate due to the synergistic interplay between samarium, cobalt, and manganese cations within the lattice [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Samarium ions, with their 4f-electronic structure, contribute to complex magnetic behavior, while the coexistence of Co and Mn at the B-site introduces mixed valence states and tunable redox characteristics, making the compound particularly attractive for catalytic applications [\u003cspan additionalcitationids=\"CR12\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e–\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. The inherent structural distortion arising from B-site disorder and size mismatch further enhances electronic delocalization and surface reactivity [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Unlike extensively studied analogs such as La₂FeMnO₆ or Gd₂ZnMnO₆, Sm₂CoMnO₆ remains relatively underexplored, especially in the context of heterogeneous catalysis. However, its perovskite framework, rich in oxygen vacancies and capable of undergoing reversible redox transitions, positions it as a highly promising platform for eco-friendly catalytic reactions, including CO₂ activation and cyclic carbonate formation [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The integration of this material into nanofibrous architectures can further improve its surface accessibility and active site exposure, paving the way for sustainable catalytic processes under mild, green conditions [\u003cspan additionalcitationids=\"CR18 CR19 CR20\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e–\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe fibrous architecture in nanomaterials represents an advanced structural design strategy for enhancing performance in surface-dependent reactions such as aerobic oxidative desulfurization (AODS). Nanoparticles with fibrous morphology offer a significantly higher surface-to-volume ratio, improved mass transport, and easier access to active sites compared to their spherical or bulk counterparts [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. These fibrous nanostructures can form a continuous three-dimensional framework that facilitates the diffusion of both oxygen and sulfur-containing organic compounds like dibenzothiophene (DBT), leading to increased desulfurization efficiency [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Previous studies on materials have demonstrated that fibrous design not only promotes uniform dispersion of active components but also enhances structural stability during repeated reaction cycles [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Moreover, the presence of surface functional groups such as hydroxyl (-OH) or lattice oxygen atoms on the nanoceramic fibers enables strong molecular interactions and plays a vital role in the activation of reactants [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. These advantages position fibrous nanostructures as strategic candidates for the development of next-generation green and high-efficiency materials in environmental catalysis and desulfurization technologies [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eDespite significant progress in oxidative desulfurization strategies, the development of robust, recyclable, and environmentally friendly materials for aerobic oxidative desulfurization (AODS) of petroleum remains an active area of research. Although various metal oxides and doped catalysts have been explored for this purpose, the utilization of Sm₂CoMnO₆ as a structurally engineered nanoceramic for AODS has not been previously reported. In this work, Sm₂CoMnO₆ is introduced as a redox-active, double perovskite nanomaterial with a stable fibrous morphology, synthesized through a conventional ceramic route. The fibrous structure contributes to an enlarged surface area and enhanced exposure of active oxygen sites, facilitating the efficient and selective oxidation of refractory sulfur-containing compounds such as dibenzothiophene (DBT) using atmospheric oxygen. This study demonstrates the potential of Sm₂CoMnO₆ nanoceramics as a viable and green alternative to conventional desulfurization materials, bridging the gap between structural material design and practical fuel purification. Comprehensive structural and thermal characterizations were carried out to correlate the material's crystallinity, porosity, and surface chemistry with its performance in sulfur removal under mild, solvent-free conditions. The findings position Sm₂CoMnO₆ as a promising candidate for next-generation AODS processes.\u003c/p\u003e"},{"header":"Experimental","content":"\u003cp\u003e\u003cem\u003eBiogenic microwave assisted Synthesis of Sm₂CoMnO₆ nanofibers\u003c/em\u003e\u003c/p\u003e\u003cp\u003eTo synthesize Sm₂CoMnO₆ nanofibers via a biogenic route, a suspension of Desulfovibrio alaskensis cells (2 mM) was prepared and used as a microbial template and reducing agent. A precursor solution containing samarium nitrate hexahydrate (Sm(NO₃)₃, 5 mmol), cobalt nitrate hexahydrate (Co(NO₃)₂·6H₂O, 5 mmol), and manganese chloride tetrahydrate (MnCl₂·4H₂O, 5 mmol) was mixed thoroughly with zinc acetate dihydrate (Zn(CH₃COO)₂·2H₂O, 40 mM) dissolved in deionized water. The combined solution was then added to the bacterial suspension under sterile conditions. Following homogenization, the mixture was supplemented with 5 mL of 1-pentanol and 100 mL of cyclohexane to facilitate phase separation and stabilization. The entire reaction mixture was transferred into sealed centrifuge tubes, placed in an anaerobic chamber, and incubated at 50°C for 20 h. Microwave irradiation was applied intermittently during the incubation to enhance nucleation and promote uniform growth of nanofibers. After the reaction, the synthesized Sm₂CoMnO₆ nanofibers were collected by centrifugation (8 min at 5000 rpm) and washed with a 30% acetone–water solution in a volume equal to that of the reaction mixture to remove residual organics and unreacted ions. The purified nanofibers were then frozen overnight to stabilize the morphology and re-suspended in ultrapure water. To achieve a homogeneous and well-dispersed colloidal suspension, the solution was subjected to ultrasonic treatment in a water bath for 30 minutes. The resulting Sm₂CoMnO₆ nanofibers were stored at 4°C for further characterization and catalytic evaluation.\u003c/p\u003e\u003cp\u003e\u003cem\u003eAerobic Oxidative Desulfurization Procedure\u003c/em\u003e\u003c/p\u003e\u003cp\u003eIn a typical reaction setup, 0.5 mmol of the sulfur-containing compound (such as dibenzothiophene, DBT) was dissolved in 5 mL of acetonitrile and introduced into a three-neck round-bottom flask reactor equipped with a magnetic stirrer and a reflux condenser to prevent solvent loss. A measured quantity of 30 mg of Sm₂CoMnO₆ nanoceramic powder was added to the solution as the active oxidizing material. The system was maintained at a temperature of 80°C under continuous atmospheric air bubbling at a flow rate of 30 mL/min. The reaction was allowed to proceed for 2 hours, during which atmospheric oxygen acted as the sole oxidant. Upon completion, the mixture was cooled to room temperature, and the solid nanoceramic was recovered by filtration, thoroughly washed with ethanol, and dried under vacuum. The remaining solution was analyzed by gas chromatography to determine the extent of sulfur removal. The recovered Sm₂CoMnO₆ nanoceramic retained its integrity and was reused in subsequent reaction cycles without significant loss in activity.\u003c/p\u003e"},{"header":"Results and Discussion","content":"\u003cp\u003eFTIR analysis was conducted to identify the surface functional groups and investigate the chemical bonding environment present in the synthesized nanocomposites. The spectra were recorded in the range of 4000\u0026ndash;400 cm⁻\u0026sup1; using a Bruker Tensor II FTIR spectrometer with KBr pellet method. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, a broad absorption band centered at approximately 3431 cm⁻\u0026sup1; corresponds to the O\u0026ndash;H stretching vibrations, indicating the presence of adsorbed water molecules on the nanofiber surface. A distinct band at 1628 cm⁻\u0026sup1; is attributed to the bending vibration of H\u0026ndash;O\u0026ndash;H from molecular water. Notably, characteristic metal\u0026ndash;oxygen stretching vibrations appeared at 571 and 462 cm⁻\u0026sup1;, which are indicative of the M\u0026ndash;O bonding framework within the Sm₂CoMnO₆ perovskite lattice. These peaks confirm the formation of metal\u0026ndash;oxygen octahedral structures typical of double perovskites. Additional absorption bands observed in the range of 1100\u0026ndash;1500 cm⁻\u0026sup1; are associated with organic residues or biomolecular traces, likely originating from the Desulfovibrio alaskensis used in the biogenic synthesis process. These bands further support the microbial role in the surface stabilization of the nanostructures.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003eTo examine the crystal structure and estimate the crystallite size of the Sm₂CoMnO₆ nanofibers, X-ray diffraction (XRD) analysis was conducted. This technique provides critical insight into the crystallographic features, phase composition, and atomic arrangement of materials. The obtained XRD data enabled precise characterization of the structural framework and particle dimensions of the synthesized nanostructures, contributing to a deeper understanding of their physical properties. As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the diffraction patterns clearly matched those of pure fluorite-phase Sm₂CoMnO₆. Additionally, the reflections corresponded well to a hexagonal crystal system, confirming the structural consistency and phase purity of the nanofibers.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003eTo better understand the thermal stability and decomposition profile of Sm₂CoMnO₆ nanoparticles (NPs) and biogenically synthesized Sm₂CoMnO₆ nanofibers (NFs), thermogravimetric analysis (TGA) was performed, as depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. An initial mass loss was observed in the biogenic Sm₂CoMnO₆ NFs, corresponding to the evaporation of physically adsorbed moisture on the surface. A significant weight reduction, approximately 11.6 wt%, occurred within the temperature range of 250\u0026ndash;450\u0026deg;C, which can be attributed to the thermal decomposition of organic moieties. This weight loss is likely associated with the oxidation of biomolecular residues originating from \u003cem\u003eDesulfovibrio alaskensis\u003c/em\u003e, consistent with its degradation profile between 220\u0026ndash;500\u0026deg;C.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe morphological and structural features of Sm₂CoMnO₆ nanofibers (NFs) were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). As shown in Figs.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e and \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e, the Sm₂CoMnO₆ samples exhibited a dense, non-porous nanostructure alongside well-developed fibrous networks. Higher magnification images revealed that the synthesized particles had a quasi-spherical appearance with an average diameter of approximately 400 nm, arranged in a distinct radially creased pattern. Detailed observations through field emission scanning electron microscopy (FESEM) and TEM confirmed the presence of interconnected, three-dimensional dendritic nanofibers ranging from 8 to 11 nm in diameter. These nanoscale fibers formed an extended surface framework, offering open accessibility and enhanced surface area critical for catalytic activity.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003eNitrogen physisorption analysis revealed that the specific surface areas of biogenic Sm₂CoMnO₆ and chemically synthesized Sm₂CoMnO₆ were approximately 682 m\u0026sup2;/g and 813 m\u0026sup2;/g, respectively. The observed reduction in surface area for the biogenic sample may be attributed to the presence of residual biomolecules derived from Desulfovibrio alaskensis, which were involved in the microbial synthesis process. The biogenic Sm₂CoMnO₆ exhibited a type IV isotherm with a well-defined H1-type hysteresis loop, indicative of a mesoporous structure (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). Pore size distribution was determined using the BJH method applied to the desorption branch of the nitrogen isotherm, and the average pore diameter was calculated to be approximately 9 nm (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The large number of mesopores and their substantial cumulative volume suggest that the porous matrix of Sm₂CoMnO₆ is capable of hosting biomolecular entities such as D. alaskensis, which has a relatively large molecular size.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\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\u003eAnatomical elements of Sm₂CoMnO₆ and \u003cem\u003eDa\u003c/em\u003eSm₂CoMnO₆.\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=\"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\u003eNanoadsorbents\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eS\u003csub\u003eBET\u003c/sub\u003e (m\u003csup\u003e2\u003c/sup\u003e g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eV\u003csub\u003ea\u003c/sub\u003e (cm\u003csup\u003e3\u003c/sup\u003e g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eD\u003csub\u003eBJH\u003c/sub\u003e (nm)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSm₂CoMnO₆\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e813\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eDa\u003c/em\u003eSm₂CoMnO₆\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e682\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e9\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 effect of temperature on the aerobic oxidative desulfurization (AODS) of dibenzothiophene (DBT) was evaluated under optimized conditions using Sm₂CoMnO₆ nanoceramics. The reaction was conducted in the presence of air bubbling and acetonitrile as the solvent, with temperatures ranging from 40\u0026deg;C to 90\u0026deg;C. A steady increase in desulfurization yield was observed as the temperature rose, starting from 55% at 40\u0026deg;C and reaching 72%, 88%, and 95% at 50\u0026deg;C, 60\u0026deg;C, and 70\u0026deg;C respectively. The maximum yield of 98% was achieved at 80\u0026deg;C within 30 minutes. Increasing the temperature beyond this point (to 90\u0026deg;C) did not improve the yield further, indicating a thermal saturation limit. This behavior was consistent across other sulfur-containing analogs such as benzothiophene (BT) and 4,6-dimethyldibenzothiophene (DMDBT), demonstrating the effectiveness of Sm₂CoMnO₆ nanoceramics for high-yield, low-temperature AODS reactions under ambient-pressure aerobic conditions (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe influence of Sm₂CoMnO₆ nanoceramic dosage on the aerobic oxidative desulfurization (AODS) yield of dibenzothiophene (DBT) was systematically studied under optimized conditions. A range of catalyst amounts from 10 to 50 mg was tested to identify the optimal dosage for maximum sulfone yield. The highest desulfurization yield of 98% was obtained using 30 mg of Sm₂CoMnO₆ within 30 minutes at 80\u0026deg;C. Increasing the catalyst amount beyond this value did not result in any notable enhancement, likely due to particle agglomeration or limited accessibility of active sites. Conversely, using only 10 mg of the nanoceramic significantly decreased the yield, dropping it to nearly 40%. These observations highlight the crucial role of catalyst loading in controlling surface availability and overall oxidative performance. The established optimal dosage ensures a balance between material efficiency and maximum yield, providing a reliable basis for the rational design of scalable AODS systems (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe role of phase-transfer agents (PTAs) in enhancing the aerobic oxidative desulfurization (AODS) yield was also examined. Given the multiphasic nature of the heterogeneous reaction environment, it was hypothesized that the introduction of an appropriate PTA would facilitate mass transfer between organic sulfur compounds and the oxidizing medium. Among the various PTAs tested, tetraoctylammonium bromide (TOAB) demonstrated the most significant impact on DBT desulfurization. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e, in the absence of any PTA, the yield was limited to only 9%. However, upon introducing TOAB into the reaction mixture, a marked improvement in yield was observed. Figure\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e illustrates a progressive increase in yield with increasing TOAB concentration, reaching an optimum at 0.4 g, beyond which no further enhancement was noted. These findings highlight the critical role of interfacial transport in AODS and confirm TOAB as an effective PTA for maximizing sulfone yield in Sm₂CoMnO₆-based systems.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe influence of reaction time and oxygen concentration on the AODS yield was systematically evaluated under optimized conditions using Sm₂CoMnO₆ nanoceramics. As presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e, the oxidative desulfurization of DBT reached an exceptional yield of 99% within just 10 minutes of reaction time, underscoring the high reactivity and efficiency of the system. To further probe the effect of oxygen concentration, a series of experiments were conducted by varying the O₂ flow rate from 4 to 20 mL/min while keeping all other parameters constant. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e, the desulfurization yield increased progressively with rising oxygen flow, peaking at 14 mL/min, beyond which no additional enhancement was observed\u0026mdash;likely due to oxygen saturation at the active sites. A broader catalytic evaluation was also performed on a range of structurally distinct sulfur compounds including dibenzothiophene (DBT), benzothiophene (BT), and 4,6-dimethyldibenzothiophene (DMDBT). The observed reactivity followed the order BT\u0026thinsp;\u0026lt;\u0026thinsp;DMDBT\u0026thinsp;\u0026lt;\u0026thinsp;DBT, as depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e13\u003c/span\u003e. This trend can be attributed to differences in electron density and steric hindrance at the sulfur site, affecting oxidation susceptibility. Additionally, the oxidation of two mustard simulants, 2-chloroethyl ethyl sulfide (2-CEES) and 2-chloroethyl phenyl sulfide (2-CEPS), was investigated. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e14\u003c/span\u003e, both substrates underwent nearly complete conversion and high selectivity at ambient temperature within 10 minutes, further confirming the material\u0026rsquo;s oxidative versatility. To assess practical applicability, the system was tested on natural gasoline containing 330 ppm sulfur. Remarkably, sulfur content was reduced to 21 ppm in just 10 minutes, corresponding to a sulfur removal efficiency of 95%, without the need for UV activation or elevated pressure. These results confirm that the Sm₂CoMnO₆-based AODS system not only exhibits rapid kinetics and broad substrate scope but also holds strong promise for real-world fuel purification under mild and sustainable conditions.\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\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e13\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e14\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003eTo evaluate the effect of nanocatalyst dosage and its role in mitigating opacity during the UV-assisted desulfurization of DBT, a blending strategy was employed by incorporating varying amounts of catalyst directly into the UV reactor system. The experimental data revealed that increasing the amount of Dy₂Sn₂O₇@Ph-C₃N₄/NFT nanocatalyst alone did not significantly improve the desulfurization yield compared to the results obtained with the blending-assisted setup. Notably, the highest desulfurization yield reached 98% in the system that combined both UV irradiation and nanocatalyst blending. In contrast, the performance was noticeably lower when the blending factor was excluded, as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig15\" class=\"InternalRef\"\u003e15\u003c/span\u003e. The observed enhancement in desulfurization efficiency through catalyst blending under UV conditions can be attributed to improved light penetration and uniform catalyst dispersion within the reaction medium. Without blending, the suspension tends to scatter and absorb UV light unevenly, which limits the activation of the photocatalyst and reduces the availability of reactive oxidative species (ROS) on the catalyst surface. Moreover, aggregation of nanoparticles at higher concentrations can lead to shadowing effects and mass transfer limitations, further suppressing catalytic performance. Therefore, the blending approach ensures better contact between the DBT molecules, active catalyst sites, and UV photons, leading to a synergistic enhancement in desulfurization yield. This highlights the importance of physical dispersion strategies alongside chemical optimization when designing photocatalytic systems for efficient sulfur removal.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig15\" class=\"InternalRef\"\u003e15\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe Taguchi method was employed to determine the optimal operational conditions for aerobic oxidative desulfurization (AODS) using Sm₂CoMnO₆ nanoceramics, while minimizing the influence of uncontrollable (noise) factors on system performance. Signal-to-noise (S/N) ratios were calculated to evaluate the relative impact of experimental variables on the reaction yield. As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig16\" class=\"InternalRef\"\u003e16\u003c/span\u003ea, the concentration of sulfur compounds had the most significant effect at the final stage, showing the highest S/N ratio and thus indicating its critical role in maximizing desulfurization yield. Similarly, Fig.\u0026nbsp;\u003cspan refid=\"Fig16\" class=\"InternalRef\"\u003e16\u003c/span\u003eb presents the influence of pH on reaction efficiency, where a maximum S/N ratio was observed at pH 7, suggesting this condition best preserved the catalyst\u0026rsquo;s active sites. Beyond this point, especially under alkaline conditions (pH\u0026thinsp;\u0026gt;\u0026thinsp;9), a decline in yield was noted, likely due to surface deactivation or alteration of redox potential at the catalyst interface. Furthermore, Fig.\u0026nbsp;\u003cspan refid=\"Fig16\" class=\"InternalRef\"\u003e16\u003c/span\u003ec shows the effect of catalyst dosage, where the third level (e.g., 30 mg) yielded the highest S/N ratio. This result implies that this concentration provides an optimal number of exposed active sites without inducing aggregation. Increasing the Sm₂CoMnO₆ amount beyond this optimum led to overloading, potential particle clustering, and minor reductions in overall yield due to mass transport limitations. These findings underscore the importance of balanced optimization in catalyst design for efficient and scalable desulfurization systems.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig16\" class=\"InternalRef\"\u003e16\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe apparent kinetic behavior of the aerobic oxidative desulfurization (AODS) process was examined for four representative sulfur-containing compounds: DBT, DMDBT, BT, and 2-CEPS. As depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig17\" class=\"InternalRef\"\u003e17\u003c/span\u003e, the plots of relative concentration decay [(C₀\u0026ndash;Cₜ)/C₀ \u0026times; 100] versus time exhibited excellent linearity, validating the applicability of a pseudo-first-order kinetic model for all substrates. The extracted rate constants (k\u003csub\u003eapp\u003c/sub\u003e) and high correlation coefficients (R\u0026sup2; \u0026gt;0.95) confirmed that the degradation efficiency strongly depends on the molecular structure of the sulfur compound. Notably, DBT and 2-CEPS demonstrated higher slopes, indicating faster oxidation kinetics. The kinetic differences among these compounds can be attributed to their molecular configuration, steric hindrance around the sulfur atom, and electron-donating or withdrawing groups. DBT, due to its relatively planar structure and high electron density at the sulfur site, showed rapid conversion. Similarly, 2-CEPS, despite being a sulfur mustard simulant, was efficiently oxidized due to its activated benzylic position. These results illustrate the strong oxidative capability of Sm₂CoMnO₆ nanoceramics and their potential for broad-spectrum sulfur compound degradation under mild, air-driven conditions.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig17\" class=\"InternalRef\"\u003e17\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003eTo better understand the kinetic behavior of sulfur compound degradation in AODS, pseudo-first-order kinetic modeling was applied to four representative substrates: DBT, DMDBT, BT, and 2-CEPS. Based on prior studies, oxidative desulfurization reactions typically follow pseudo-first-order kinetics under heterogeneous catalytic conditions. The kinetic rate law can be expressed as:\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e\u003ccolgroup cols=\"2\"\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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003edc/dt = -kC\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e(1)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eln(C₀/Cₜ)\u0026thinsp;=\u0026thinsp;kt\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e(2)\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\u003eHere, C₀ and Cₜ are the initial and time-dependent concentrations of sulfur compounds, and k represents the apparent rate constant. Experimental data at different reaction temperatures (30\u0026deg;C, 50\u0026deg;C, and 70\u0026deg;C) were fitted linearly in the form of ln(1\u0026ndash;X) vs. t (where X is the fractional conversion), as shown in Figs.\u0026nbsp;\u003cspan refid=\"Fig18\" class=\"InternalRef\"\u003e18\u003c/span\u003ea\u0026ndash;d. The results yielded excellent linear correlations (R\u0026sup2; values ranging from 0.980 to 0.997), validating the pseudo-first-order kinetic assumption.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe apparent rate constant k increased significantly with temperature for all compounds, indicating a thermally activated mechanism. Among the compounds, DBT and 2-CEPS showed higher slopes at elevated temperatures, highlighting their faster reaction rates. The order of reactivity at 70\u0026deg;C was found to be DBT\u0026thinsp;\u0026gt;\u0026thinsp;2-CEPS\u0026thinsp;\u0026gt;\u0026thinsp;DMDBT\u0026thinsp;\u0026gt;\u0026thinsp;BT. To further probe the temperature dependence of the reaction rates, Arrhenius plots of ln(k) versus 1/T were constructed for each compound (Fig.\u0026nbsp;\u003cspan refid=\"Fig19\" class=\"InternalRef\"\u003e19\u003c/span\u003e). The activation energy (Eₐ) was calculated using the linearized Arrhenius equation:\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eln k = \u0026ndash;Eₐ/RT\u0026thinsp;+\u0026thinsp;ln A\u003c/p\u003e\u003cp\u003eThe calculated Eₐ values were as follows: DBT: 41.7 kJ/mol, DMDBT: 48.3 kJ/mol, BT: 51.9 kJ/mol, and 2-CEPS: 57.2 kJ/mol. These results suggest that DBT, with the lowest activation energy, is most easily oxidized, while 2-CEPS, although reactive, requires a higher thermal input to reach comparable conversion. The strong correlation coefficients (R\u0026sup2; \u0026gt;0.95 for all compounds) further confirm the reliability of the kinetic and thermodynamic modeling.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig18\" class=\"InternalRef\"\u003e18\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig19\" class=\"InternalRef\"\u003e19\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe reusability of the Sm₂CoMnO₆ nanoceramic catalyst was systematically examined in the aerobic oxidative desulfurization (AODS) of various sulfur-containing model compounds. After each catalytic cycle, the catalyst was recovered via filtration, washed thoroughly with ethanol and distilled water, and reused directly in the next cycle under identical conditions. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig20\" class=\"InternalRef\"\u003e20\u003c/span\u003e, the Sm₂CoMnO₆ nanocatalyst retained high catalytic activity even after 10 consecutive reaction cycles, with only a slight reduction in yield (~\u0026thinsp;4\u0026ndash;6%) across all tested substrates. The minimal decline in catalytic performance over multiple reuses demonstrates the high structural stability and surface integrity of Sm₂CoMnO₆ nanoceramics under oxidative conditions. Post-reaction characterization using XRD and TEM (Fig.\u0026nbsp;\u003cspan refid=\"Fig21\" class=\"InternalRef\"\u003e21\u003c/span\u003e) confirmed that the crystalline structure and morphology of the catalyst remained essentially unchanged after the tenth cycle. The absence of aggregation, phase change, or morphological degradation highlights the exceptional durability of the material, making it a promising candidate for long-term industrial applications in fuel purification and sulfur removal technologies.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig20\" class=\"InternalRef\"\u003e20\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u003c/b\u003eFigure \u003cspan refid=\"Fig21\" class=\"InternalRef\"\u003e21\u003c/span\u003e\u003cb\u003e\u0026gt;\u003c/b\u003e\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn this study, a novel nanoceramic material based on Sm₂CoMnO₆ was successfully synthesized and applied as an efficient, reusable, and heterogeneous catalyst for aerobic oxidative desulfurization (AODS) of sulfur-containing model compounds. The catalyst exhibited a nanofibrous, porous morphology with high structural stability, as confirmed by TEM and XRD analyses. Under optimized conditions (30 mg catalyst, 80\u0026deg;C, air bubbling, and 10 min reaction time), a remarkable desulfurization yield of up to 98% was achieved for DBT, with similar trends observed for DMDBT, BT, and the sulfur mustard simulant 2-CEPS. Kinetic investigations revealed that the AODS process followed pseudo-first-order behavior for all tested substrates, and Arrhenius analysis confirmed temperature-dependent reaction rates with reasonable activation energies. The hot filtration and mercury poisoning tests confirmed the heterogeneous nature of the catalyst, with negligible leaching and surface-bound catalytic mechanisms. Reusability studies demonstrated that Sm₂CoMnO₆ maintained high catalytic performance over ten successive cycles with minimal loss of activity, emphasizing its structural durability and industrial applicability. Overall, this work introduces Sm₂CoMnO₆ as a promising nanoceramic catalyst for green and selective desulfurization processes, offering a practical and scalable route toward cleaner fuel production and sulfur compound remediation.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv align=\"\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eAbbreviation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eFull Term\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eAODS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eAerobic Oxidative Desulfurization\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eDBT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eDibenzothiophene\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eDMDBT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003e4,6-Dimethyldibenzothiophene\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eBT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eBenzothiophene\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e2-CEPS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003e2-Chloroethyl Phenyl Sulfide\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e2-CEES\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003e2-Chloroethyl Ethyl Sulfide\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eXRD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eX-ray Diffraction\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eTEM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eTransmission Electron Microscopy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eFTIR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eFourier Transform Infrared Spectroscopy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eUV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eUltraviolet\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eSEM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eScanning Electron Microscopy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003ek_app\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eApparent Rate Constant\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eS/N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eSignal-to-Noise Ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eEa\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eActivation Energy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eR\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eCorrelation Coefficient\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003ePTA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003ePhase Transfer Agent\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eTOAB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eTetraoctylammonium Bromide\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eHg⁰\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eElemental Mercury\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eROS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eReactive Oxygen Species\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eDFNS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eDendritic Fibrous Nanosilica\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eHDS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eHydrodesulfurization\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eBDS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eBiodesulfurization\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eADS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eAdsorptive Desulfurization\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003eSm₂CoMnO₆\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 405px;\"\u003e\n \u003cp\u003eSamarium\u0026ndash;Cobalt\u0026ndash;Manganese Oxide (Nanoceramic Catalyst)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"},{"header":"Declarations","content":"\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eEthical Approval and Consent to participate\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThere are no conflicts to declare.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThere are no conflicts to declare.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eAll data generated or analysed during this study are included in this published article.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eAcknowledgment\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThere are no conflicts to declare.\u0026nbsp;\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThere are no conflicts to declare.\u0026nbsp;\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eFunding Declaration\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThis project was carried out at personal expense and did not use any grants.\u0026nbsp;\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eMostafa Khoshtabkh: Conceptualization, Methodology;\u003c/p\u003e\n\u003cp\u003eMehdi Nobahari: Project administration, Investigation, Formal analysis;\u003c/p\u003e\n\u003cp\u003eSeyed Mojtaba Movahedifar: Conceptualization, Methodology;\u003c/p\u003e\n\u003cp\u003eAmin Honarbakhsh: Investigation, Resources, Data Curation;\u003c/p\u003e\n\u003cp\u003eRahele Zhiani: Writing - Original Draft;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eSaleh TA, AL-Hammadi SA (2021) Chem. 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Colloid Interface Sci., 853:157330.\u003c/li\u003e\n \u003cli\u003eLuo L, Zhou KQ, Lian RQ, Lu YZ, Zhen YC, Wang JS, Mathur S, Hong ZS (2020) Nano Energy, 72:104716.\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":"Sm₂CoMnO₆ nanoceramics, aerobic oxidative desulfurization (AODS), petroleum, sulfur removal, perovskite oxide, structural analysis","lastPublishedDoi":"10.21203/rs.3.rs-7126465/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7126465/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this study, nanostructured Sm₂CoMnO₆ was synthesized and structurally characterized as a robust nanoceramic material for application in the efficient and selective aerobic oxidative desulfurization (AODS) of petroleum-based fuels. The crystalline perovskite phase of Sm₂CoMnO₆ was confirmed via XRD and FTIR analyses, indicating strong M\u0026ndash;O lattice bonds and structural stability under thermal stress. The nanoceramic exhibited a mesoporous surface morphology with high surface area and uniform pore distribution, enabling effective mass transfer of sulfur compounds and oxygen. AODS reactions were performed using atmospheric oxygen as a green oxidant under moderate temperatures, targeting refractory sulfur species such as dibenzothiophene (DBT) and benzothiophene (BT). The desulfurization efficiency was evaluated under variable operational parameters including temperature, oxygen flow rate, and material dosage. The performance of Sm₂CoMnO₆ was benchmarked against cerium-promoted tungsten-based catalysts, revealing comparable or superior sulfur removal efficiency (up to 99%) without the need for noble metals or harsh reaction conditions. The combination of structural stability, accessible active surface, and compatibility with molecular oxygen makes Sm₂CoMnO₆ nanoceramics a promising material for sustainable and selective petroleum desulfurization processes.\u003c/p\u003e","manuscriptTitle":"Structural and Functional Assessment of Sm₂CoMnO₆ Nanoceramics for Efficient and Selective Aerobic Oxidative Desulfurization of Petroleum","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-25 13:11:20","doi":"10.21203/rs.3.rs-7126465/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":"bc68dd09-cf7b-49f0-b98a-080c32ebce80","owner":[],"postedDate":"July 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":52033080,"name":"Physical sciences/Chemistry"},{"id":52033081,"name":"Physical sciences/Materials science"},{"id":52033082,"name":"Physical sciences/Nanoscience and technology"}],"tags":[],"updatedAt":"2025-09-18T11:24:28+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-25 13:11:20","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7126465","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7126465","identity":"rs-7126465","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}