Engineering Cu Supported Y-Zeolite Catalysts for the Selective Conversion of γ-Valerolactone to Methyl Tetrahydrofuran

Engineering Cu Supported Y-Zeolite Catalysts for the Selective Conversion of γ-Valerolactone to Methyl Tetrahydrofuran | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Engineering Cu Supported Y-Zeolite Catalysts for the Selective Conversion of γ-Valerolactone to Methyl Tetrahydrofuran G. Hima Bindu, S. Vittal, M. Shanti, S. Shylaja, T. Krishna, Rakesh Chilivery This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6865530/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 16 Dec, 2025 Read the published version in Waste and Biomass Valorization → Version 1 posted 5 You are reading this latest preprint version Abstract A sustainable approach to chemistry is achieved by utilizing heterogeneous catalysts for the synthesis of chemicals derived from biomass. Using impregnation, Cu/Y-Zeolite catalysts were prepared in this work for hydrogenating γ-valerolactone (GVL) to methyl tetrahydrofuran (MTHF). X-ray diffraction (XRD), Temperature programmed reduction (TPR-H 2 ), Temperature programmed desorption (TPD-NH 3 ), UV-DRS, and HR-TEM were used for characterization of the synthesized catalysts in terms of their structure, surface, electronic and spectroscopic attributes. The Lewis and Bronsted acidity further confirmed by Py-IR spectroscopy. The N 2 O decomposition studies reveals the copper surface area and copper particle size. When GVL was hydrogenated using a 5CYZ catalyst at a temperature of 250°C and a hydrogen pressure of 0.1MPa, the GVL conversion rate reached 92.1%, and the selectivity for MTHF was 84%. To achieve optimal conversion of GVL to MTHF with high selectivity, reaction conditions such as temperature, GVL input rate, and catalyst amount were fine-tuned. Y-zeolite copper γ-valerolactone methyltetrahydrofuran 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 1. Introduction The creation of renewable chemicals typically requires less energy and produces fewer greenhouse gases than traditional petroleum-based processes [ 1 ][ 2 ]. Furthermore, chemicals sourced from biomass can be biodegradable, which aids in reducing the accumulation of harmful substances in the environment[ 3 ][ 4 ]. This transition to bio-based options also supports the growth of a circular economy, where waste can be reused and recycled, thereby reducing environmental harm [ 5 ]. γ-Valerolactone (GVL), derived from lignocellulose, is one of the most versatile platform chemicals from biomass[ 6 ]. GVL can be transformed into valuable substances, such as adipic acid, an essential precursor for nylon, 1,4 Pentanediol (PDO) and 2-methyltetrahydrofuran (MTHF), a promising biofuel additive[ 7 ][ 8 ]. Furthermore, its low toxicity, high boiling point, and stability render it an exceptional green solvent for a variety of industrial applications, thereby enhancing its potential as a sustainable alternative to petroleum-based chemicals. The widespread adoption of GVL and other bio-based chemicals could significantly reduce our dependence on fossil fuels and mitigate environmental impacts[ 9 ][ 10 ]. This shift towards renewable resources aligns with global sustainability goals and supports the development of a more resilient and eco-friendly chemical industry. Moreover, the versatility of GVL as both a platform chemical and a green solvent opens up new possibilities for innovative and sustainable product development across various sectors [ 11 ]. In recent times, there has been an increasing focus on generating 2-methyltetrahydrofuran from renewable resources [ 9 ]. This compound is seen as a promising additive for biofuels due to its beneficial properties, such as high energy density and compatibility with existing fuel systems. Additionally, MTHF can be synthesized from a range of biomass-derived precursors, making it an attractive option for sustainable fuel production. Research has mainly concentrated on creating efficient catalytic methods for MTHF synthesis. Recent advancements in heterogeneous catalysis have led to improved yields and selectivity in converting biomass-derived materials into MTHF[ 12 ]. Furthermore, integrating MTHF production into current biorefinery operations offers exciting opportunities for cost-effective and sustainable fuel production on an industrial scale. A major challenge in producing MTHF is optimizing catalytic processes to achieve higher conversion rates and minimizing unwanted byproducts. Researchers are investigating innovative catalyst designs, such as bimetallic and supported nanoparticle catalysts, to enhance the overall efficiency of the synthesis. Additionally, efforts are being made to develop integrated biorefinery systems that can seamlessly incorporate MTHF production alongside other value-added products, maximizing resource utilization and economic viability. The production of chemicals from biomass using heterogeneous catalysts aligns seamlessly with the principles of sustainable chemistry[ 13 ]. This approach not only reduces reliance on fossil fuel-derived feedstocks but also mitigates environmental impact by utilizing renewable resources. Heterogeneous catalysts are particularly advantageous for large-scale biomass conversion due to their ease of separation, reusability, and potential for continuous processing. Furthermore, the development of new catalytic materials and processes in this field opens up opportunities for creating value-added products from agricultural and forestry waste, thereby supporting a circular bioeconomy. The use of noble metals like platinum, palladium, and ruthenium has shown promising results in the hydrogenation of GVL to valuable chemicals such as 1,4-pentanediol and 2-methyltetrahydrofuran. However, the high cost and limited availability of these noble metals have prompted researchers to explore alternative catalytic systems. Recent studies have focused on developing non-noble metal catalysts, such as those based on nickel and copper, which offer similar activity and selectivity at more cost-effective prices[ 14 ]. These advancements in non-noble metal catalysts have the potential to significantly reduce production costs and make biomass-derived chemicals more competitive with their fossil fuel-based counterparts [ 15 ]. Y zeolites serve as outstanding support materials for the stabilization and dispersion of active phase metal oxides, thanks to their extensive specific surface areas[ 16 ][ 17 ]. The impregnation of various metal oxides into zeolites enhances the interaction between the host and the guest materials [ 18 ]. The unique pore structure of Y zeolites allows for controlled distribution of metal oxide particles within the zeolite framework. Furthermore, the acidity of Y zeolites can be tailored to complement the catalytic properties of the incorporated metal oxides, creating synergistic effects in various chemical reactions [ 19 ]. This synergy between the zeolite support and metal oxide active phase often leads to improved catalytic performance and selectivity. The high thermal stability of Y zeolites also contributes to the longevity of the catalysts under harsh reaction conditions. Additionally, the well-defined pore structure of Y zeolites enables shape-selective catalysis, allowing for precise control over product formation in complex reaction systems [ 20 ]. This research focuses on investigating the vapor phase hydrogenation of GVL to MTHF at atmospheric pressure, utilizing copper oxide supported on a y-zeolite substrate. The copper-supported y-zeolite catalyst was prepared through the impregnation method and subsequently characterized using XRD, UV-DRS, TPD-NH 3 , ICP, BET, TPR-H 2 , SEM, and TEM techniques. Py-IR spectroscopy further confirmed the presence of Lewis and Bronsted acidity. N2O decomposition studies provided insights into the copper surface area and particle size. Furthermore, the study investigates the influence of reaction parameters such as temperature and GVL concentration, as well as the catalyst's stability over time, providing valuable information for optimizing the hydrogenation process. 2. EXPERIMENTAL SECTION 2.1 Catalyst preparation Cu/Y-zeolite catalysts were prepared through the impregnation method. A commercially available Y-zeolite support (CBV-760 type, SiO 2 /Al 2 O 3 ratio-60) was mixed with copper nitrate and distilled water in a flask, and the mixture was stirred at 60°C until the water evaporated. The resulting products were then dried overnight at 100°C and subsequently calcined in air at 500°C for 5 hours. The final catalysts are designated as XCuY-Z, where X indicates the copper loading (5, 10, and 15 wt.%). 2.2 Characterization The X-ray powder diffraction patterns for all samples were collected using a D8 Diffractometer (Advance, Bruker, Germany), employing Cu Kα radiation (1.5406 A°) at 40 kV and 30 mA. Nitrogen adsorption-desorption isotherms were measured using Autosorb-1 (Quanta Chrome instruments, USA) at -196°C after the samples were outgassed at 250°C to eliminate any physically adsorbed species. The UV-Vis diffused reflectance spectra were obtained using a GBC UV-Visible Cintra 10e spectrometer equipped with an integrating sphere reflectance accessory. Studies involving temperature-programmed reduction and temperature-programmed desorption (NH 3 -TPD) were carried out using the Auto Chem 2910 instrument from Micromeritics, USA. In a standard procedure, 0.1g of an oven-dried specimen was placed in a U-shaped quartz sample tube and secured with a quartz wool plug. Before conducting TPR studies, the catalyst sample underwent a pretreatment by flowing He gas at 200°C for 2 hours. Following the pretreatment, the sample was allowed to cool to room temperature, and TPR analysis was performed in a flow of 5H 2 /Ar, increasing the temperature from room temperature to 500ºC at a rate of 10 ºC/min. In a standard procedure for TPD investigations, following pre-treatment such as TPR, the sample was saturated with a mixture of 10NH 3 -He at 80°C for 1 hour and then purged with helium flow at 140°C for 2 hours to eliminate any physisorbed ammonia. TPD analysis was performed from room temperature to 600 ºC with a heating rate of 10 ºC/min. The quantity of NH 3 that was desorbed was determined utilizing the GRAMS/32 software. 2.3 Catalytic reaction The hydrogenation reaction was conducted in a standard down flow fixed-bed glass reactor featuring an inner diameter of 0.9cm, maintained at ambient pressure. About 0.3g of the catalyst was combined with an equivalent mass of glass beads, which were supported on the ceramic wool bed within the reactor. Before the reaction, the catalyst samples underwent in-situ reduction in a hydrogen stream at 350ºC for duration of 2 hours. Upon reaching the designated reaction temperature, an aqueous solution containing 10wt% GVL was introduced into the reactor. The liquid products were systematically collected on an hourly basis in an ice-cold trap and subsequently subjected to analysis utilizing the HP5973 quadruple GC-MSD system equipped with an HP-1MS capillary column. 3. RESULTS AND DISCUSSIONS 3.1 Characterization results XRD analysis was performed to investigate the crystal structure of the Cu within the support material. Figure 1 displays the XRD patterns of the YZ, 5CYZ, 10CYZ, and 15CYZ catalysts, Fig. 1 shows the XRD patterns of Y-zeolite (JCPDS:43–0168). Importantly, all diffraction peaks typical of zeolite Y were present, and no impurities were detected[ 21 ]. At a copper loading of 5wt%, the catalyst did not exhibit distinct copper oxide peaks, suggesting the presence of highly dispersed amorphous copper oxide species[ 22 ].The absence of distinct copper oxide peaks at lower loadings suggests a strong interaction between the copper species and the support material, potentially enhancing catalytic activity. When the loading reached 10wt%, the XRD reflections of crystalline CuO emerged (JCPDS:45–0937)[ 23 ]. The observable peaks in Fig. 1 correspond to the (002), (111), (200), (202), (202), (113), (311), (113), and (220) planes of monoclinic space group C2/c, respectively [ 24 ][ 25 ]. The average particle size was calculated using Scherrer’s formula: D = 0.9k/βcosɵ, with the results shown in Table.2. As the Cu loading increased, the intensity of the CuO XRD peaks increased, indicating improved CuO crystalline. The lack of distinct peaks at lower loadings suggests that the well-dispersed copper species may interact closely with the support material. Furthermore, the XRD data facilitated the identification of any potential impurities or secondary phases in the sample, confirming the absence of impurity phases. The XRD analysis provided valuable insights into the structural characteristics of the copper-loaded catalysts. The absence of distinct copper oxide peaks at lower loadings suggests a strong interaction between the copper species and the support material, potentially enhancing catalytic activity. This information is crucial for optimizing catalyst performance and understanding structure-property relationships in heterogeneous catalysis. Figure 2 shows the N 2 isotherms for all prepared samples. Each sample exhibits typical type 1 adsorption, indicating that they were microporous materials. Nonetheless, a type H4 hysteresis was detected, indicating the existence of mesopores and narrow slit pores in all materials. This porosity can enhance the mass transport and accessibility to active sites within the material. Further analysis of the pore-size distribution would provide more detailed insights into the specific pore characteristics of each sample. Table 1 presents the BET surface areas, average pore sizes, and pore volumes of the YZ, 5CYZ, 10CYZ, and 15CYZ catalysts. Initially, the Brunauer-Emmett-Teller (BET) surface area of YZ was 523.5 m 2 /gm. Upon the addition of copper, this area decreases to 491.2 m 2 /gm and continued to decline with further copper loading, as the CuO crystallites obstructed the pores. The average pore size of YZ was 2.265 nm, which decreased slightly to 2.145 nm for 5CYZ, and further to 1.741 nm for 15CYZ. This decrease in pore size can be attributed to the blockage of smaller pores by CuO particles, leaving larger pores more accessible. The pore volume followed a similar trend to the surface area, decreasing from 0.351 to 0.313, 0.291, and 0.264 cc/g for 5CYZ, 10CYZ, and 15CYZ, respectively. The observed changes in surface area, pore size, and pore volume indicate that copper loading significantly affects the structural properties of the catalysts. These alterations in the catalyst's physical characteristics could potentially impact its catalytic performance and selectivity in various reactions. The copper concentration was determined through ICP analysis, and the results are presented in Table 1. The ICP analysis indicated that the copper concentration closely aligns with the theoretical value. Table.1: ICP and surface area of Z, 5CZ, 10CZ and 15CZ samples Catalyst Cu content (Wt.%) a BET surface area (m 2 /gm) b Average pore diameter b (nm) Total Pore Volume b (cc/g) Z - 523.5 2.265 0.351 5CZ 4.18 491.2 2.145 0.313 10CZ 8.96 454.2 1.912 0.291 15CZ 15.06 425.3 1.741 0.264 a- ICP analysis b- BET analysis UV-Visible Diffuse Reflectance Spectroscopy (UV-DRS) is a crucial technique for examining Cu-supported samples, particularly for catalysis and materials science. This method provides important insights into the electronic structure, oxidation states, and ligand environments of the copper species. Figure 3 shows the UV-DRS spectra of the 5CYZ, 10CYZ, and 15CYZ catalysts. All samples showed a peak in the UV-DRS spectrum near 210 nm, which corresponds to the charge-transfer transition between Cu 2+ and oxygen ions[ 26 ][ 27 ]. Moreover, a shoulder-like band was observed at 235 nm, which was attributed to ligand-to-metal charge transfer between the surface oxygen and isolated Cu 2+ ions. The intensity of this band is related to the Cu content in the samples, underscoring its connection with Cu-related species. These spectral features provide essential insights into the electronic structure and coordination environment of copper ions within the catalyst framework. NH 3 -TPD is an invaluable method for assessing the surface acidities of heterogeneous catalysts. This technique allows the analysis of acid sites on catalyst surfaces to evaluate their strength, distribution, and concentration. The desorption profiles are shown in Fig. 4 . Pure YZ exhibited three desorption peaks (Zone1, Zone2, and Zone3) at approximately 150, 350, and 500°C, which correspond to weak, moderate, and strong acidic sites. According to the literature, ammonia desorption peaks in the ranges–100–200°C, 200–450°C, and above 450°C are attributed to weak, moderate, and strong acidic sites, respectively [ 24 ]. Upon the addition of copper to the YZ support, the weakly acidic sites gradually diminished owing to the copper coverage. This effect was more pronounced in the 15CYZ sample because the large CuO crystallites obstructed the acidic sites of YZ. Additionally, the presence of Cu introduced new catalytic sites, enhancing the overall efficiency of the catalytic process. As indicated in the table, increasing the Cu loading from 5 to 15CYZ results in a gradual decrease in the total acidity of the CYZ catalysts. The observed decrease in total acidity with increasing Cu loading can be attributed to the progressive coverage of YZ acidic sites by copper species. This trend suggests that the copper content plays a crucial role in modulating the surface acidity of the CYZ catalysts. Furthermore, the introduction of new catalytic sites by Cu incorporation may compensate for the loss of acidity, potentially leading to a more balanced and efficient catalytic performance. Scanning electron microscopy (SEM) was employed to investigate the morphology of the zeolite samples. Figure 5 displays SEM images of both Y-zeolite and Cu-containing Y-zeolites. Figure 5 a presents typical micrographs of microcrystalline zeolite Y, where a significant crystal size of about 1.0 µm is noticeable. Figure 6 illustrates the distribution maps of Al, Si, and Cu on the surface of the 5CuYZ catalyst. The mapping image of Cu (Fig. 6 ) reveals that it was uniformly distributed across the 5CuYZ support. This even distribution of copper suggests an effective dispersion of the active metal on the YZ surface, which is vital for catalytic performance. Such a consistent distribution likely enhances the accessibility of reactants to the active sites. The uniform copper distribution on the zeolite surface indicates a high level of metal dispersion, which is essential for maximizing catalytic activity. This even spread of active sites can result in increased reaction rates and improved overall catalytic efficiencies. Additionally, the well-dispersed copper particles may contribute to the catalyst's enhanced stability during extended use. Transmission electron microscopy (TEM) was employed to examine the microstructure of 5CYZ and the distribution of copper. As shown in Fig. 7 , the entire YZ maintains a consistent structure, aligning with the results from SEM. The copper particles appear to be uniformly dispersed throughout the YZ matrix, with no visible agglomeration or clustering. This homogeneous distribution of copper suggests effective incorporation during the synthesis process. The acidic characteristics of the Cu-containing Y-zeolite were evaluated by quantitative IR analysis of pyridine adsorption, as depicted in Fig. 8 . This highly basic molecule is commonly employed to identify the types and numbers of Brønsted and Lewis acid sites in solid catalysts. When pyridine interacts with Brønsted sites, it receives a proton, forming pyridinium ions, which are detected by the bands at 1550–1540 cm -1 [ 28 ]. Conversely, Lewis acid sites, which accept electron pairs, coordinate with pyridine, resulting in PyL bands in the 1460–1430 cm -1 range[ 29 ]. The position of the PyL band indicates the strength of the Lewis sites; a higher position indicates a greater number of electron acceptors. The IR spectra of pyridine adsorbed on the Cu-containing Y-zeolite samples revealed both the Brønsted and Lewis acid sites. The intensity of the PyL band at 1452 cm -1 increased with increasing copper content, signifying an increase in Lewis acidity. These findings suggest that incorporation of Cu into the zeolite structure enhanced the number of Lewis acid sites, potentially affecting the catalytic behavior of the material. Interestingly, as the copper content in the Y-zeolite increased, there was an increase in Lewis acid sites, accompanied by a decrease in the number of Bronsted acid sites. This phenomenon can be attributed to the replacement of protons in the zeolite framework by copper ions during the preparation process, and the observed trade-off between Lewis and Brønsted acidities with increasing copper content has significant implications for the catalytic properties of Cu-containing Y-zeolites. This balance between the acid site types can be fine-tuned by adjusting the copper loading, allowing for the optimization of the catalytic performance in specific reactions. Furthermore, the ability to control the acid-site distribution opens up possibilities for tailoring these materials for a wide range of applications in heterogeneous catalysis. The size of the copper particles was evaluated through N 2 O decomposition. As indicated in Table 2, the particle size grew with an increase in Cu loading. This observation is supported by XRD and SEM analyses, which suggest that the larger particle size at higher copper loadings is due to greater agglomeration during synthesis. This agglomeration could influence the catalytic performance of copper particles, possibly diminishing their total surface area and active sites. Table.2: N 2 O decomposition measurements results of various CYZ catalysts Catalyst Crystallite size a (nm) H 2 2nd uptake b (mole/g) Particle size b (nm) YZ - - - 5CYZ 5.1 0.012 6.7 10CYZ 8.9 0.008 10.2 15CYZ 19.7 0.004 22.3 a-XRD, b- N 2 O decomposition studies 3.2 Catalytic activity: As illustrated in Fig. 9 , we explored the impact of varying the metal loading on the catalytic performance in the hydrogenation of GVL using different CYZ catalysts. Several products were generated during this process, including 2-methyltetrahydrofuran, 1,4 pentanediol, pentenoic acid, valeric acid, 1-pentanol, and 2-pentanol, with MTHF and PDO as the primary products. The formation of these various products underscores the complexity of the GVL hydrogenation process. Optimizing the yield of the desired products, especially MTHF and PDO, requires careful control of the reaction conditions and catalyst selection. The conversion of γ-valerolactone (GVL) to methyl tetrahydrofuran (MTHF) involves a series of reactions including hydrogenation and dehydration. Initially, the carbonyl group in GVL is hydrogenated to form a 2-hydroxymethyltetrahydrofuran intermediate. This intermediate was further hydrogenated to 5-hydroxy pentanone, which was then hydrogenated to produce PDO. Finally, PDO undergoes cyclisation to form the target compound, methyl tetrahydrofuran. The transformation of GVL to MTHF is intricate, necessitating precise control of the reaction conditions and catalysts to achieve a high selectivity and yield. The other products resulted from over-hydrogenation. The choice of the catalyst is crucial for determining the efficiency and specificity of each step in the reaction sequence. The figure shows that the Bare YZ support was inactive for GVL hydrogenation. However, when copper was loaded onto YZ, the activity significantly increased from 4.0–92.1%, indicating the vital role of copper in the conversion of GVL to MTHF. Under ambient pressure and a reaction temperature of 250°C, the GVL conversion decreased from 92.1–69.4% as the Cu loading increased from 5 to 15 wt. %, with selectivity also decreasing from 92.1 to 69.4%. It was demonstrated that 5CYZ achieved the best and most optimized GVL conversion and MTHF selectivity of 92.1% and 84%, respectively. The high diffusivity of copper in YZ allows it to exhibit maximum catalytic activity owing to its superior Cu dispersion, smaller particle sizes, and strong acidic site availability. Temperature and pressure during the reaction are critical parameters that significantly influence the reaction kinetics and product distribution in the hydrogenation process. The enhanced dispersion of Cu particles and strong acidic sites on the support surface was attributed to the synergistic effect of Cu and YZ on the catalyst surface, suggesting that an optimal balance between metal loading and the catalyst support is crucial for maximizing GVL conversion and MTHF selectivity. Higher copper loadings of more than 5 wt. % appear to have a detrimental effect on catalytic performance, possibly due to reduced dispersion or blockage of active sites. Further investigation of the relationship between copper loading, particle size distribution, and acid site density could provide valuable insights for catalyst optimization in this reaction system. In the Fig. 10 , it is evident that the size of the copper particles affects the MTHF yield. As the particle size increases from 5.1 to 19.7 nm, there is a gradual decrease in the MTHF yield. This trend suggests that smaller copper particles are more effective catalysts for the production of MTHF. The increased surface area-to-volume ratio of smaller particles likely provides more active sites for the reaction to occur. Further investigation into the optimal particle size range could lead to improved catalyst design and enhanced MTHF yields in industrial applications. Reaction conditions: 10% GVL, 0.3g catalyst, 0.5ml/hour, 250°C and 0.1MPa hydrogen pressure. This study examined how varying reaction temperature affects the catalytic performance of GVL hydrogenation using a 5CYZ catalyst, with temperatures between 200–300°C and hydrogen pressure of 0.1MPa, as shown in Fig. 11 . As temperature increased from 200 to 300°C, GVL conversion increased from 53.2–100%, whereas MTHF selectivity declined from 89.1–72.5%. Complete GVL conversion was achieved at 275°C. At lower temperatures (200–225°C), GVL conversion was low but MTHF selectivity remained high. When temperature reached 275°C, GVL conversion improved to nearly 100%, and selectivity shifted towards PDO production. Results demonstrate that temperature plays a crucial role in GVL conversion and product selectivity. Increasing temperature beyond optimal conditions could lead to undesirable side reactions or decreased MTHF selectivity. The optimal reaction temperature appears to be around 250–275°C, balancing high GVL conversion with good MTHF selectivity. Above 275°C, side reactions likely become more prevalent, leading to decreased MTHF selectivity and increased formation of byproducts. These results demonstrate the importance of carefully controlling reaction temperature to maximize desired product yields in GVL hydrogenation using the 5CYZ catalyst."The optimal reaction conditions were 250°C and ambient pressure, providing the best balance between GVL conversion and MTHF selectivity. These findings suggest temperature optimization is crucial for achieving desired balance between GVL conversion and product selectivity. At 250°C, the catalyst showed optimal performance with high GVL conversion and favorable MTHF selectivity. Further research could explore fine-tuning reaction conditions or modifying catalyst composition to enhance MTHF selectivity at higher temperatures. Reaction conditions: 10% GVL, 0.3g catalyst, 0.5ml/hour and 0.1Ma hydrogen pressure. The impact of GVL loading on the 5CYZ catalyst's performance was evaluated (Fig. 12 ). As the GVL loading increased from 0.5 to 1.5 ml/hour, both GVL conversion and MTHF selectivity consistently decreased. This decline was due to the blockage of active sites by reactant molecules. Therefore, it was concluded that a GVL loading of 0.5 ml/hour is optimal for further studies. This rate was deemed ideal for efficient conversion while minimizing the obstruction of active sites, and optimizing GVL loading is essential for maintaining catalyst efficiency and maximizing product yield. Figure 13 illustrates the impact of catalyst quantities on GVL hydrogenation to MTHF at 250°C. Doubling the catalyst from 0.2 g to 0.4 g improved both LA conversion and GVL yield. The highest GVL conversion, with 74.5% selectivity for MTHF, was achieved using 0.5 g of 5CZ, indicating insufficient active sites for complete hydrogenation to MTHF. When the catalyst was adjusted to between 0.3 g and 0.4 g, decreased MTHF selectivity was observed, suggesting 0.3 g provided adequate catalytic sites for converting GVL to MTHF. Increasing catalyst to 0.3 g and 0.4 g caused a slight decline in MTHF selectivity, possibly due to over-hydrogenation or side reactions. This finding shows the importance of optimizing catalyst loading to balance conversion and selectivity. Using 0.3 g of catalyst offers the best performance, maximizing MTHF yield while minimizing unwanted byproducts. Additionally, it is crucial to investigate the long-term durability and reusability of the 5CYZ catalyst for its potential application in sustainable biofuel production on an industrial scale, as illustrated in the TOS graph in Fig. 14 . The catalyst's stability was evaluated over a 12-hour duration, maintaining an optimal GVL loading rate of 0.5 ml/hour, a reaction temperature of 250°C, and an H 2 pressure of 0.1MPa. Throughout this period, the 5CYZ catalyst exhibited remarkable stability, consistently achieving GVL conversion and MTHF selectivity. This sustained stability suggests that the 5CYZ catalyst is a strong candidate for industrial applications in converting GVL to MTHF. The catalyst's performance remained consistent, with no significant decrease in activity or selectivity observed over the extended reaction period. This stability can be attributed to the robust structure and composition of the 5CYZ catalyst, which effectively resists deactivation under the given reaction conditions. According to the literature, all catalysts mentioned showed enhanced activity when subjected to high-pressure environments. Notably, the 5CYZ catalyst exhibited the best catalytic performance, achieving a GVL conversion rate of % and MTHF selectivity of 82% at 250°C under atmospheric H 2 pressure (Fig. 15 ). The exceptional performance of the 5CZ catalyst was due to its distinctive structural characteristics and improved Cu dispersion. The exceptional catalytic performance of the 5CYZ catalyst, achieving a high GVL conversion rate and MTHF selectivity at 250°C under atmospheric H 2 pressure, suggests that its smaller particle size plays a crucial role. The improved Cu dispersion likely contributes to a larger active surface area, allowing for more efficient catalytic reactions. The ability of the catalyst to maintain a high selectivity towards MTHF indicates that it effectively promotes the desired reaction pathway while minimizing unwanted side reactions. Further investigation of the specific structural features and surface properties of the 5CYZ catalyst could provide valuable insights for the development of more efficient catalysts for similar applications. 4. Conclusions This study investigates the vapor-phase hydrogenation of GVL to MTHF at atmospheric pressure using copper oxide supported on YZ. The YZ catalyst with copper was prepared via the impregnation method and analyzed using XRD, UV-DRS, TPD-NH3, ICP, BET, TPR-H 2 , XPS, SEM, and TEM. When GVL was hydrogenated with the 5CYZ catalyst at 250°C and 0.1Mpa, a GVL conversion rate of 92.1% and an MTHF selectivity of 84% were obtained. The improved dispersion of the Cu particles and the presence of strong acidic sites on the support surface were attributed to the synergistic interaction between Cu and YZ in the 5CYZ catalyst. Over a 12-hour duration, the 5CYZ catalyst exhibited remarkable stability, maintaining consistent GVL conversion and MTHF selectivity. This long-term stability suggests that the 5CYZ catalyst is promising for industrial applications in the conversion of GVL to MTHF. This study contributes to the growing body of knowledge in green chemistry processes, could lead to more efficient and environmentally friendly production of valuable chemicals from renewable resources, and has significant implications for the development of sustainable chemical processes. The high conversion rate and selectivity achieved with the 5CYZ catalyst demonstrated its potential for the efficient production of MTHF from GVL. Declarations Funding This project did not receive any external funding or additional grants. Acknowledgements The all authors thanks to Department of Chemistry, CVR College of Engineering Hyderabad, India. CRCL, New Delhi, India, G. Narayanamma Institute of Technology and Sciences, Hyderabad, India. Department of Chemistry, Chaitanya Bharathi Institute of Technology, Hyderabad, India. Department of Chemistry, University College of Science Hyderabad, India References Khawaja, A.S., Zaheer, M.A., Ahmad, A., Mirani, A.A., Ali, Z., Advances in limitations and opportunities of clean biofuel production to promote decarbonization, Fuel. 342, 127662 (2023). https://doi.org/10.1016/j.fuel.2023.127662. Stancin, H., Mikulcic, H., Wang, X., Duic, N., A review on alternative fuels in future energy system, Renew. Sustain. Energy Rev. 128, 109927 (2020). https://doi.org/10.1016/j.rser.2020.109927. Sun, P.T., Peng, H., Valorisation of Biomass Waste for Sustainable Bioenergy and Biofuel Production, Bioengineering. 10, 4 (2023). https://doi.org/10.3390/bioengineering10050619. Mignogna, D., Szabo, M., Ceci, P., Avino, P., Biomass Energy and Biofuels: Perspective, Potentials, and Challenges in the Energy Transition, Sustain. 16, 1 (2024). https://doi.org/10.3390/su16167036. Oumer, A.N., Hasan, M.M., Baheta, A.T., Mamat, R., Abdullah, A.A., Bio-based liquid fuels as a source of renewable energy: A review, Renew. Sustain. Energy Rev. 88, 82 (2018). https://doi.org/10.1016/j.rser.2018.02.022. Khalid, M., Granollers Mesa, M., Scapens, D., Osatiashtiani, A., Advances in Sustainable γ-Valerolactone (GVL) Production via Catalytic Transfer Hydrogenation of Levulinic Acid and Its Esters, ACS Sustain. Chem. Eng. (2024). https://doi.org/10.1021/acssuschemeng.4c05812. Ponnala, B., Rajendiran, R., Vijayanand P., Selvaraj, M., Rokhum, S.L., Balla, P., Kim, S., Engineering acidic and Pt sites on WO 3 - doped H-mordenite supported Pt catalyst for hydrogenation of γ -valerolactone to methyl tetra hydrofuran, Mol. Catal. 559 (2024) 114065. https://doi.org/10.1016/j.mcat.2024.114065. Putrakumar, B., Kumar, S.P., Rao, G.S., Pethan Rajan, N., Bhanuchander, P., Raveendra, G., Vijayanand, P., Lassi, U., Bakhsh, E.M., S.B. Khan, S. Kim, Copper nanoparticles encapsulated in a nanoporous carbon-based catalyst in the upgradation of γ-valerolactone to 1,4-pentanediol by selective hydrogenation, Mater. Today Sustain. 22, 1000406 (2023). https://doi.org/10.1016/j.mtsust.2023.100406. Banerjee, D., Sahu, A.K., Clegg, J.K., Upadhyayula, S., Recent advances in 2-methylfuran production via catalytic transfer hydrogenation of biomass-derived furfural, Chem. Eng. J. 493, 152552 (2024). https://doi.org/10.1016/j.cej.2024.152552. Rackemann, D.W., W.O. Doherty, The conversion of lignocellulosics to levulinic acid, Biofuels, Bioprod. Biorefining. 5 (2011) 198–214. https://doi.org/10.1002/bbb.267. Huerta-Rosas, B., Coronel-Muñoz, M., Quiroz-Ramírez, J.J., Cáceres-Barrera, C.R., Contreras-Zarazúa, G., Segovia-Hernández, J.G., Sánchez-Ramírez, E., Intensified alternative for sustainable gamma-valerolactone production from levulinic acid, Chem. Eng. Res. Des. 217, 38 (2025). https://doi.org/10.1016/j.cherd.2025.03.023. Tuan Hoang, A, Viet Pham, V., 2-Methylfuran (MF) as a potential biofuel: A thorough review on the production pathway from biomass, combustion progress, and application in engines, Renew. Sustain. Energy Rev. 148,111 (2021) 111265. https://doi.org/10.1016/j.rser.2021.111265. Naranov, E., Sustainable Production of Chemicals via Hydrotreating of CO 2 and Biomass Derived Molecules Using Heterogeneous Noble Metal Oxide Catalysts, ChemCatChem. 16, 1 (2024). https://doi.org/10.1002/cctc.202301268. Liu, Z., Zhang, R., Liu, H., Zhang, J., Sun, Y., Li, N., Peng, L., Effect of carbon modifier on characteristics and catalytic properties of zeolite–carbon hybrid supported Zr towards γ-valerolactone production, Fuel. 359, 130380 (2024). https://doi.org/10.1016/j.fuel.2023.130380. Zhang, G., Ma, L., Dong, Y., Fang, Y., Kong, X., Fabrication of hierarchical flower-like NiMo bimetallic catalyst for valorization of biomass platforms, Fuel. 333, 126400 (2023). https://doi.org/10.1016/j.fuel.2022.126400. Ruscher, C.H., Salman, N., Buhl, J.C, Lutz, W., Relation between growth-size and chemical composition of X and Y type zeolites, Microporous Mesoporous Mater. 92, 309 (2006). 10.1016/j.micromeso.2006.01.016 Senila, M., Cadar, O., Modification of natural zeolites and their applications for heavy metal removal from polluted environments: Challenges, recent advances, and perspectives, Heliyon. 10, 25303 (2024). https://doi.org/10.1016/j.heliyon.2024.e25303. Lang, Q., Lu, P., Yang, X., Valtchev, V., Zeolites for the environment, Green Carbon. 2, 12 (2024). https://doi.org/10.1016/j.greenca.2024.02.007. Ferrarelli, G., Migliori, M., Catizzone, E., Recent Trends in Tailoring External Acidity in Zeolites for Catalysis, ACS Omega. 9, 29072 (2024). https://doi.org/10.1021/acsomega.4c03899. Narayanan, S., Tamizhdurai, P., Mangesh, V.L., Ragupathi, C., Santhana krishnan, P., Ramesh, A., Recent advances in the synthesis and applications of mordenite zeolite - review, RSC Adv. 11, 250 (2020). https://doi.org/10.1039/d0ra09434j. Janiga, J., Investigation of phase purity of faujasite-type Y zeolite, Zeolites. 10, 38 (1990). https://doi.org/10.1016/0144-2449(90)90092-6. Banerjee, S., Sarkar, S., Sarkar, S., Patra A.K., Rational design of self-assembled copper oxide nanoparticles into hierarchical nanorods with high-surface-area for environmental remediation of wastewater, Inorg. Chem. Commun. 160, 111925 (2024). https://doi.org/10.1016/j.inoche.2023.111925. Balla, P., Seelam, P.K., Rajenidran, R., Balaga, R., Challa, P., Perupogu, V., Lassi, U., Sungtak, K., Selective hydrogenation of levulinic acid over a highly dispersed and stable copper particles embedded into the ordered mesoporous carbon supported catalyst, Catal. Commun. 178, 106673 (2023). https://doi.org/10.1016/j.catcom.2023.106673. Shoja Razavi, R., Loghman-Estarki, M.R., Synthesis and Characterizations of Copper Oxide Nanoparticles Within Zeolite Y, J. Clust. Sci. 23,1097 (2012). https://doi.org/10.1007/s10876-012-0502-y. Zhakypov, A.S., Nemkayeva, R.R., Yerlanuly, Y., Tulegenova, M.A., Kurbanov, B.Y., Aitzhanov, M.B., Markhabayeva, A.A., Gabdullin, M.T., Synthesis and in situ oxidation of copper micro- and nanoparticles by arc discharge plasma in liquid, Sci. Rep. 13, 1 (2023). https://doi.org/10.1038/s41598-023-41631-2. Silva, M., Baltrus, J.P., Williams, C., Knopf, A., Zhang, L., Baltrusaitis, J., Heterogeneous photo-Fenton-like degradation of emerging pharmaceutical contaminants in wastewater using Cu-doped MgO nanoparticles, Appl. Catal. A Gen. 630, 118468 (2022). https://doi.org/10.1016/j.apcata.2021.118468. Pothu, R., Challa, P., Rajesh, R., Boddula, R., Balaga, R., Balla, P., Perugopu, V., Radwan, A.B., Abdullah, A.M., Al-Qahtani, N., Vapour-Phase Selective Hydrogenation of γ-Valerolactone to 2-Methyltetrahydrofuran Biofuel over Silica-Supported Copper Catalysts, Nanomaterials. 12, 12193414 (2022). https://doi.org/10.3390/nano12193414. Jabłońska, M., Gora-Marek, K., Bruzzese, P.C., A. Palčić, K. Pyra, K. Tarach, M. Bertmer, D. Poppitz, A. Pöppl, R. Gläser, Influence of Framework n(Si)/n(Al) Ratio on the Nature of Cu Species in Cu-ZSM-5 for NH 3 -SCR-DeNOx, ChemCatChem. 14, 627 (2022). https://doi.org/10.1002/cctc.202200627. Mitta, H., Seelam, P.K., Ojala, S., Keiski, R.L., Balla, P., Tuning Y-zeolite based catalyst with copper for enhanced activity and selectivity in vapor phase hydrogenolysis of glycerol to 1,2-propanediol, Appl. Catal. A Gen. 550, 308 (2018). https://doi.org/10.1016/j.apcata.2017.10.019. Upare, P.P., Lee, J.M., Hwang, Y.K., Hwang, D.W., Lee, J.H., Halligudi, S.B., Hwang, J.S., Chang, J.S., Direct hydrocyclization of biomass-derived levulinic acid to 2-methyltetrahydrofuran over nanocomposite copper/silica catalysts, ChemSusChem. 4, 1749 (2011) 1749–1752. https://doi.org/10.1002/cssc.201100380. Zheng, J., Zhu, J., Xu, X., Wang, W., Li, J., Zhao, Y., Tang, K., Song, Q., Qi, X., Kong, D., Tang, Y., Continuous hydrogenation of ethyl levulinate to γ-valerolactone and 2-methyl tetrahydrofuran over alumina doped Cu/SiO 2 catalyst: The potential of commercialization, Sci. Rep. 6, 28898 (2016). https://doi.org/10.1038/srep28898. Novodárszki, G., Solt, H.E.,Valyon, J., Lónyi, F., Hancsók, J., Deka, D., Tuba, R., Mihályi, M.R., Selective hydroconversion of levulinic acid to γ-valerolactone or 2-methyltetrahydrofuran over silica-supported cobalt catalysts, Catal. Sci. Technol. 9,2291 (2019). https://doi.org/10.1039/c9cy00168a. Supplementary Files Graphicalabstract.docx Cite Share Download PDF Status: Published Journal Publication published 16 Dec, 2025 Read the published version in Waste and Biomass Valorization → Version 1 posted Reviewers agreed at journal 06 Jul, 2025 Reviewers invited by journal 06 Jul, 2025 Editor invited by journal 29 Jun, 2025 Editor assigned by journal 11 Jun, 2025 First submitted to journal 10 Jun, 2025 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-6865530","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":481320722,"identity":"3a913aa6-84ec-43e1-aecc-0ad148c2c026","order_by":0,"name":"G. Hima Bindu","email":"","orcid":"","institution":"CVR College of Engineering Hyderabad: CVR College Of Engineering","correspondingAuthor":false,"prefix":"","firstName":"G.","middleName":"Hima","lastName":"Bindu","suffix":""},{"id":481320723,"identity":"5046d636-2eaa-4da2-902c-44578f9c3f0d","order_by":1,"name":"S. Vittal","email":"","orcid":"","institution":"Central revenue control laboratory","correspondingAuthor":false,"prefix":"","firstName":"S.","middleName":"","lastName":"Vittal","suffix":""},{"id":481320724,"identity":"7177c846-e39a-4282-85b1-1c41430e2c61","order_by":2,"name":"M. Shanti","email":"","orcid":"","institution":"G Narayanamma Institute of Technology and Science for Women","correspondingAuthor":false,"prefix":"","firstName":"M.","middleName":"","lastName":"Shanti","suffix":""},{"id":481320725,"identity":"d5d2f9ed-3124-4097-aaea-53dc19ed73d1","order_by":3,"name":"S. Shylaja","email":"","orcid":"","institution":"Chaitanya Bharathi Institute of Technology","correspondingAuthor":false,"prefix":"","firstName":"S.","middleName":"","lastName":"Shylaja","suffix":""},{"id":481320726,"identity":"49d6a45e-65e0-490e-b4b9-9252e708c1ff","order_by":4,"name":"T. Krishna","email":"","orcid":"","institution":"Osmania University","correspondingAuthor":false,"prefix":"","firstName":"T.","middleName":"","lastName":"Krishna","suffix":""},{"id":481320727,"identity":"524fe019-5039-4338-b155-b58dc16508e7","order_by":5,"name":"Rakesh Chilivery","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3klEQVRIiWNgGAWjYFACNgYGxgYGBgP2HiDHACJ2gDgtPGdAWgxI0SKRw4CwBh8wbz+W+PDnDgZ5c8m3x6QrCv4w8LcfYDxcgEeLzJm0w8a8ZxgMd87OS5M8A3SYxJkEhsMz8GiRYEhvk2ZsY0gwuJ1jbNgA8ssNBobDPPi08D9v//kTpOXmGYgWeYJaJNKOMfCCtNzgMXwI0mJAWMuzZGneNgnDDWfyEoFajHkMzyQ2EHBYmuHHn2028gbHzx442PBHTk7u+OHDn/FpgemEs3gg0TQKRsEoGAWjgCIAADkYR3/6NjUKAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0002-5295-440X","institution":"Padmasri Dr BV Raju Institute of Technology","correspondingAuthor":true,"prefix":"","firstName":"Rakesh","middleName":"","lastName":"Chilivery","suffix":""}],"badges":[],"createdAt":"2025-06-10 18:02:03","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6865530/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6865530/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s12649-025-03436-4","type":"published","date":"2025-12-16T15:58:09+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":86487854,"identity":"5f241eff-d794-4336-9060-d0676e61d8ff","added_by":"auto","created_at":"2025-07-11 08:34:55","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":167594,"visible":true,"origin":"","legend":"\u003cp\u003eXRD profiles of YZ, 5CYZ, 10CYZ and 15CYZ catalysts\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/c90f0f1a16dadbae0a03a761.png"},{"id":86485568,"identity":"fb0c9bb0-ba06-4f52-ae0d-31d6018f5289","added_by":"auto","created_at":"2025-07-11 08:18:54","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":79699,"visible":true,"origin":"","legend":"\u003cp\u003eN\u003csub\u003e2 \u003c/sub\u003eadsorption-desorption isotherms of YZ, 5CYZ, 10CYZ and 15CYZ catalysts\u003c/p\u003e","description":"","filename":"image2.tiff.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/80833b05827cc78884fe6bc8.jpg"},{"id":86485569,"identity":"36dec538-9001-434b-a542-695ed5dfb9c0","added_by":"auto","created_at":"2025-07-11 08:18:54","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":117068,"visible":true,"origin":"","legend":"\u003cp\u003eUVDRS spectra of YZ, 5CYZ, 10CYZ and 15CYZ catalysts\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/1769e4befb0b17bcfe8f0600.png"},{"id":86487252,"identity":"217b17e5-acad-4af3-91ec-ca97c36064c6","added_by":"auto","created_at":"2025-07-11 08:26:55","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":154221,"visible":true,"origin":"","legend":"\u003cp\u003eNH\u003csub\u003e3\u003c/sub\u003e -TPD profiles of YZ, 5CYZ, 10CYZ and 15CYZ catalysts\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/e21c46e1e8639ab3176a08a7.png"},{"id":86487249,"identity":"9c8004c5-e285-4355-912f-5578e887c2af","added_by":"auto","created_at":"2025-07-11 08:26:54","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":836184,"visible":true,"origin":"","legend":"\u003cp\u003e(a) SEM images of various CYZ catalysts, (a) YZ (b) 5CYZ (c) 10CYZ and (d) 15CYZ catalysts\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/35889d45bd112b09f4655f40.png"},{"id":86485574,"identity":"1f4c509e-a3f7-4ad0-87da-74ca9a2009ee","added_by":"auto","created_at":"2025-07-11 08:18:55","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":152083,"visible":true,"origin":"","legend":"\u003cp\u003eSEM-EDS images of 5CYZ catalyst\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/59ee23f5b83c6954e57f0fee.png"},{"id":86485580,"identity":"7ff8ccf4-c46b-4447-8092-b8a4d7e7b8c3","added_by":"auto","created_at":"2025-07-11 08:18:55","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":677490,"visible":true,"origin":"","legend":"\u003cp\u003eHR-TEM images of 5CYZ catalyst.\u003c/p\u003e","description":"","filename":"image7.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/04b23baa3f771e3dc2b564e7.png"},{"id":86485588,"identity":"d810f324-a05a-42c7-88a5-f55bbd977588","added_by":"auto","created_at":"2025-07-11 08:18:55","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":144842,"visible":true,"origin":"","legend":"\u003cp\u003ePy-IR profiles of YZ, 5CYZ, 10CYZ and 15CYZ catalysts\u003c/p\u003e","description":"","filename":"image8.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/d44771c93ab45a7bc183c9c3.png"},{"id":86487255,"identity":"926c1635-a6f5-454c-864f-a311952b0999","added_by":"auto","created_at":"2025-07-11 08:26:55","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":103572,"visible":true,"origin":"","legend":"\u003cp\u003eThe effect of copper loading of CYZ catalysts on the hydrogenation of GVL to MTHF\u003c/p\u003e","description":"","filename":"image9.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/9d10db5bb1dd931ec8a22ecc.png"},{"id":86485571,"identity":"3c5c76bb-4694-4ac8-aabb-1df74100821a","added_by":"auto","created_at":"2025-07-11 08:18:54","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":112490,"visible":true,"origin":"","legend":"\u003cp\u003eThe correlation of particle size and activity.\u003c/p\u003e","description":"","filename":"image10.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/a801de0fe270d8fa0e1f79dc.png"},{"id":86487855,"identity":"6270d9f4-6150-496f-a6a9-b02eaca4920b","added_by":"auto","created_at":"2025-07-11 08:34:55","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":16670,"visible":true,"origin":"","legend":"\u003cp\u003eThe effect of reaction temperature on the hydrogenation of GVL to MTHF over 5CYZ catalyst.\u003c/p\u003e","description":"","filename":"image11.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/b9463c0d88cefe776752cd22.png"},{"id":86488841,"identity":"f1c689b0-dc23-41b3-9348-3195527f1cf1","added_by":"auto","created_at":"2025-07-11 08:42:55","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":117038,"visible":true,"origin":"","legend":"\u003cp\u003eThe effect of GVL feeding on the hydrogenation of GVL to MTHF over 5CYZ catalyst\u003c/p\u003e","description":"","filename":"image12.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/0eb18d26c010f975af79eea0.png"},{"id":86485589,"identity":"52da4dbb-e37c-4ca4-8b74-a990b81ec6c8","added_by":"auto","created_at":"2025-07-11 08:18:55","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":92924,"visible":true,"origin":"","legend":"\u003cp\u003eThe effect of catalyst loading on the hydrogenation of GVL to MTHF over 5CYZ catalyst\u003c/p\u003e","description":"","filename":"image13.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/51d3f27c767ae14872c12ea8.png"},{"id":86487259,"identity":"6d3a6b9a-bee3-49f8-861c-5eba63ee38fb","added_by":"auto","created_at":"2025-07-11 08:26:55","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":117963,"visible":true,"origin":"","legend":"\u003cp\u003eThe time on steam study over 5CYZ catalyst\u003c/p\u003e","description":"","filename":"image14.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/2e105e90f7fab20da2be6b0c.png"},{"id":86485592,"identity":"6ed654a3-cf64-42cd-8700-8197eda30ae9","added_by":"auto","created_at":"2025-07-11 08:18:55","extension":"png","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":179151,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of copper based catalysts for the GVL to MTHF reaction.\u003c/p\u003e\n\u003cp\u003e(NiCu/SiO\u003csub\u003e2\u003c/sub\u003e[30], Cu/Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e-SiO\u003csub\u003e2\u003c/sub\u003e[31], Cu/Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e[30], Co/SiO\u003csub\u003e2\u003c/sub\u003e[32], Cu/SiO\u003csub\u003e2\u003c/sub\u003e [27] and CuYZ (TW-This work)\u003c/p\u003e","description":"","filename":"image15.png","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/b1b0317dd916b762cf4aaf96.png"},{"id":98815225,"identity":"2721bf97-eb3a-4b40-b1cb-ff40d77d021d","added_by":"auto","created_at":"2025-12-22 16:14:12","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3799373,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/a261b5e4-fb41-477f-8371-baa84d1bd2f6.pdf"},{"id":86488840,"identity":"ddcadd5e-0a8d-41e2-928c-b560748c8077","added_by":"auto","created_at":"2025-07-11 08:42:55","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":271611,"visible":true,"origin":"","legend":"","description":"","filename":"Graphicalabstract.docx","url":"https://assets-eu.researchsquare.com/files/rs-6865530/v1/06f417dfb5161945bc06d557.docx"}],"financialInterests":"","formattedTitle":"Engineering Cu Supported Y-Zeolite Catalysts for the Selective Conversion of γ-Valerolactone to Methyl Tetrahydrofuran","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe creation of renewable chemicals typically requires less energy and produces fewer greenhouse gases than traditional petroleum-based processes [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e][\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Furthermore, chemicals sourced from biomass can be biodegradable, which aids in reducing the accumulation of harmful substances in the environment[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e][\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. This transition to bio-based options also supports the growth of a circular economy, where waste can be reused and recycled, thereby reducing environmental harm [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. γ-Valerolactone (GVL), derived from lignocellulose, is one of the most versatile platform chemicals from biomass[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. GVL can be transformed into valuable substances, such as adipic acid, an essential precursor for nylon, 1,4 Pentanediol (PDO) and 2-methyltetrahydrofuran (MTHF), a promising biofuel additive[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e][\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Furthermore, its low toxicity, high boiling point, and stability render it an exceptional green solvent for a variety of industrial applications, thereby enhancing its potential as a sustainable alternative to petroleum-based chemicals. The widespread adoption of GVL and other bio-based chemicals could significantly reduce our dependence on fossil fuels and mitigate environmental impacts[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e][\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. This shift towards renewable resources aligns with global sustainability goals and supports the development of a more resilient and eco-friendly chemical industry. Moreover, the versatility of GVL as both a platform chemical and a green solvent opens up new possibilities for innovative and sustainable product development across various sectors [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn recent times, there has been an increasing focus on generating 2-methyltetrahydrofuran from renewable resources [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. This compound is seen as a promising additive for biofuels due to its beneficial properties, such as high energy density and compatibility with existing fuel systems. Additionally, MTHF can be synthesized from a range of biomass-derived precursors, making it an attractive option for sustainable fuel production. Research has mainly concentrated on creating efficient catalytic methods for MTHF synthesis. Recent advancements in heterogeneous catalysis have led to improved yields and selectivity in converting biomass-derived materials into MTHF[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Furthermore, integrating MTHF production into current biorefinery operations offers exciting opportunities for cost-effective and sustainable fuel production on an industrial scale. A major challenge in producing MTHF is optimizing catalytic processes to achieve higher conversion rates and minimizing unwanted byproducts. Researchers are investigating innovative catalyst designs, such as bimetallic and supported nanoparticle catalysts, to enhance the overall efficiency of the synthesis. Additionally, efforts are being made to develop integrated biorefinery systems that can seamlessly incorporate MTHF production alongside other value-added products, maximizing resource utilization and economic viability.\u003c/p\u003e\u003cp\u003eThe production of chemicals from biomass using heterogeneous catalysts aligns seamlessly with the principles of sustainable chemistry[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. This approach not only reduces reliance on fossil fuel-derived feedstocks but also mitigates environmental impact by utilizing renewable resources. Heterogeneous catalysts are particularly advantageous for large-scale biomass conversion due to their ease of separation, reusability, and potential for continuous processing. Furthermore, the development of new catalytic materials and processes in this field opens up opportunities for creating value-added products from agricultural and forestry waste, thereby supporting a circular bioeconomy. The use of noble metals like platinum, palladium, and ruthenium has shown promising results in the hydrogenation of GVL to valuable chemicals such as 1,4-pentanediol and 2-methyltetrahydrofuran. However, the high cost and limited availability of these noble metals have prompted researchers to explore alternative catalytic systems. Recent studies have focused on developing non-noble metal catalysts, such as those based on nickel and copper, which offer similar activity and selectivity at more cost-effective prices[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. These advancements in non-noble metal catalysts have the potential to significantly reduce production costs and make biomass-derived chemicals more competitive with their fossil fuel-based counterparts [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eY zeolites serve as outstanding support materials for the stabilization and dispersion of active phase metal oxides, thanks to their extensive specific surface areas[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e][\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The impregnation of various metal oxides into zeolites enhances the interaction between the host and the guest materials [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The unique pore structure of Y zeolites allows for controlled distribution of metal oxide particles within the zeolite framework. Furthermore, the acidity of Y zeolites can be tailored to complement the catalytic properties of the incorporated metal oxides, creating synergistic effects in various chemical reactions [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. This synergy between the zeolite support and metal oxide active phase often leads to improved catalytic performance and selectivity. The high thermal stability of Y zeolites also contributes to the longevity of the catalysts under harsh reaction conditions. Additionally, the well-defined pore structure of Y zeolites enables shape-selective catalysis, allowing for precise control over product formation in complex reaction systems [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThis research focuses on investigating the vapor phase hydrogenation of GVL to MTHF at atmospheric pressure, utilizing copper oxide supported on a y-zeolite substrate. The copper-supported y-zeolite catalyst was prepared through the impregnation method and subsequently characterized using XRD, UV-DRS, TPD-NH\u003csub\u003e3\u003c/sub\u003e, ICP, BET, TPR-H\u003csub\u003e2\u003c/sub\u003e, SEM, and TEM techniques. Py-IR spectroscopy further confirmed the presence of Lewis and Bronsted acidity. N2O decomposition studies provided insights into the copper surface area and particle size. Furthermore, the study investigates the influence of reaction parameters such as temperature and GVL concentration, as well as the catalyst's stability over time, providing valuable information for optimizing the hydrogenation process.\u003c/p\u003e"},{"header":"2. EXPERIMENTAL SECTION","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Catalyst preparation\u003c/h2\u003e\u003cp\u003eCu/Y-zeolite catalysts were prepared through the impregnation method. A commercially available Y-zeolite support (CBV-760 type, SiO\u003csub\u003e2\u003c/sub\u003e/Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e ratio-60) was mixed with copper nitrate and distilled water in a flask, and the mixture was stirred at 60\u0026deg;C until the water evaporated. The resulting products were then dried overnight at 100\u0026deg;C and subsequently calcined in air at 500\u0026deg;C for 5 hours. The final catalysts are designated as XCuY-Z, where X indicates the copper loading (5, 10, and 15 wt.%).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Characterization\u003c/h2\u003e\u003cp\u003eThe X-ray powder diffraction patterns for all samples were collected using a D8 Diffractometer (Advance, Bruker, Germany), employing Cu Kα radiation (1.5406 A\u0026deg;) at 40 kV and 30 mA. Nitrogen adsorption-desorption isotherms were measured using Autosorb-1 (Quanta Chrome instruments, USA) at -196\u0026deg;C after the samples were outgassed at 250\u0026deg;C to eliminate any physically adsorbed species. The UV-Vis diffused reflectance spectra were obtained using a GBC UV-Visible Cintra 10e spectrometer equipped with an integrating sphere reflectance accessory. Studies involving temperature-programmed reduction and temperature-programmed desorption (NH\u003csub\u003e3\u003c/sub\u003e-TPD) were carried out using the Auto Chem 2910 instrument from Micromeritics, USA. In a standard procedure, 0.1g of an oven-dried specimen was placed in a U-shaped quartz sample tube and secured with a quartz wool plug. Before conducting TPR studies, the catalyst sample underwent a pretreatment by flowing He gas at 200\u0026deg;C for 2 hours. Following the pretreatment, the sample was allowed to cool to room temperature, and TPR analysis was performed in a flow of 5H\u003csub\u003e2\u003c/sub\u003e/Ar, increasing the temperature from room temperature to 500\u0026ordm;C at a rate of 10 \u0026ordm;C/min. In a standard procedure for TPD investigations, following pre-treatment such as TPR, the sample was saturated with a mixture of 10NH\u003csub\u003e3\u003c/sub\u003e-He at 80\u0026deg;C for 1 hour and then purged with helium flow at 140\u0026deg;C for 2 hours to eliminate any physisorbed ammonia. TPD analysis was performed from room temperature to 600 \u0026ordm;C with a heating rate of 10 \u0026ordm;C/min. The quantity of NH\u003csub\u003e3\u003c/sub\u003e that was desorbed was determined utilizing the GRAMS/32 software.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Catalytic reaction\u003c/h2\u003e\u003cp\u003eThe hydrogenation reaction was conducted in a standard down flow fixed-bed glass reactor featuring an inner diameter of 0.9cm, maintained at ambient pressure. About 0.3g of the catalyst was combined with an equivalent mass of glass beads, which were supported on the ceramic wool bed within the reactor. Before the reaction, the catalyst samples underwent in-situ reduction in a hydrogen stream at 350\u0026ordm;C for duration of 2 hours. Upon reaching the designated reaction temperature, an aqueous solution containing 10wt% GVL was introduced into the reactor. The liquid products were systematically collected on an hourly basis in an ice-cold trap and subsequently subjected to analysis utilizing the HP5973 quadruple GC-MSD system equipped with an HP-1MS capillary column.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. RESULTS AND DISCUSSIONS","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Characterization results\u003c/h2\u003e\u003cp\u003eXRD analysis was performed to investigate the crystal structure of the Cu within the support material. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e displays the XRD patterns of the YZ, 5CYZ, 10CYZ, and 15CYZ catalysts, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the XRD patterns of Y-zeolite (JCPDS:43\u0026ndash;0168). Importantly, all diffraction peaks typical of zeolite Y were present, and no impurities were detected[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. At a copper loading of 5wt%, the catalyst did not exhibit distinct copper oxide peaks, suggesting the presence of highly dispersed amorphous copper oxide species[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].The absence of distinct copper oxide peaks at lower loadings suggests a strong interaction between the copper species and the support material, potentially enhancing catalytic activity. When the loading reached 10wt%, the XRD reflections of crystalline CuO emerged (JCPDS:45\u0026ndash;0937)[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. The observable peaks in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e correspond to the (002), (111), (200), (202), (202), (113), (311), (113), and (220) planes of monoclinic space group C2/c, respectively [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e][\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. The average particle size was calculated using Scherrer\u0026rsquo;s formula: D\u0026thinsp;=\u0026thinsp;0.9k/βcosɵ, with the results shown in Table.2. As the Cu loading increased, the intensity of the CuO XRD peaks increased, indicating improved CuO crystalline. The lack of distinct peaks at lower loadings suggests that the well-dispersed copper species may interact closely with the support material. Furthermore, the XRD data facilitated the identification of any potential impurities or secondary phases in the sample, confirming the absence of impurity phases. The XRD analysis provided valuable insights into the structural characteristics of the copper-loaded catalysts. The absence of distinct copper oxide peaks at lower loadings suggests a strong interaction between the copper species and the support material, potentially enhancing catalytic activity. This information is crucial for optimizing catalyst performance and understanding structure-property relationships in heterogeneous catalysis.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the N\u003csub\u003e2\u003c/sub\u003e isotherms for all prepared samples. Each sample exhibits typical type 1 adsorption, indicating that they were microporous materials. Nonetheless, a type H4 hysteresis was detected, indicating the existence of mesopores and narrow slit pores in all materials. This porosity can enhance the mass transport and accessibility to active sites within the material. Further analysis of the pore-size distribution would provide more detailed insights into the specific pore characteristics of each sample. Table\u0026nbsp;1 presents the BET surface areas, average pore sizes, and pore volumes of the YZ, 5CYZ, 10CYZ, and 15CYZ catalysts. Initially, the Brunauer-Emmett-Teller (BET) surface area of YZ was 523.5 m\u003csup\u003e2\u003c/sup\u003e/gm. Upon the addition of copper, this area decreases to 491.2 m\u003csup\u003e2\u003c/sup\u003e/gm and continued to decline with further copper loading, as the CuO crystallites obstructed the pores. The average pore size of YZ was 2.265 nm, which decreased slightly to 2.145 nm for 5CYZ, and further to 1.741 nm for 15CYZ. This decrease in pore size can be attributed to the blockage of smaller pores by CuO particles, leaving larger pores more accessible. The pore volume followed a similar trend to the surface area, decreasing from 0.351 to 0.313, 0.291, and 0.264 cc/g for 5CYZ, 10CYZ, and 15CYZ, respectively. The observed changes in surface area, pore size, and pore volume indicate that copper loading significantly affects the structural properties of the catalysts. These alterations in the catalyst's physical characteristics could potentially impact its catalytic performance and selectivity in various reactions. The copper concentration was determined through ICP analysis, and the results are presented in Table\u0026nbsp;1. The ICP analysis indicated that the copper concentration closely aligns with the theoretical value.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eTable.1: ICP and surface area of Z, 5CZ, 10CZ and 15CZ samples\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabb\" border=\"1\"\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCatalyst\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCu content\u003c/p\u003e\u003cp\u003e(Wt.%)\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBET surface area\u003c/p\u003e\u003cp\u003e(m\u003csup\u003e2\u003c/sup\u003e/gm)\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAverage pore diameter\u003csup\u003eb\u003c/sup\u003e (nm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eTotal Pore Volume\u003csup\u003eb\u003c/sup\u003e (cc/g)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eZ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e523.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2.265\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.351\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5CZ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e491.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2.145\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.313\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e10CZ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e454.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.912\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.291\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e15CZ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e15.06\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e425.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.741\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.264\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003ea- ICP analysis\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003eb- BET analysis\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eUV-Visible Diffuse Reflectance Spectroscopy (UV-DRS) is a crucial technique for examining Cu-supported samples, particularly for catalysis and materials science. This method provides important insights into the electronic structure, oxidation states, and ligand environments of the copper species. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the UV-DRS spectra of the 5CYZ, 10CYZ, and 15CYZ catalysts. All samples showed a peak in the UV-DRS spectrum near 210 nm, which corresponds to the charge-transfer transition between Cu\u003csup\u003e2+\u003c/sup\u003e and oxygen ions[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e][\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. Moreover, a shoulder-like band was observed at 235 nm, which was attributed to ligand-to-metal charge transfer between the surface oxygen and isolated Cu\u003csup\u003e2+\u003c/sup\u003e ions. The intensity of this band is related to the Cu content in the samples, underscoring its connection with Cu-related species. These spectral features provide essential insights into the electronic structure and coordination environment of copper ions within the catalyst framework.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eNH\u003csub\u003e3\u003c/sub\u003e-TPD is an invaluable method for assessing the surface acidities of heterogeneous catalysts. This technique allows the analysis of acid sites on catalyst surfaces to evaluate their strength, distribution, and concentration. The desorption profiles are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. Pure YZ exhibited three desorption peaks (Zone1, Zone2, and Zone3) at approximately 150, 350, and 500\u0026deg;C, which correspond to weak, moderate, and strong acidic sites. According to the literature, ammonia desorption peaks in the ranges\u0026ndash;100\u0026ndash;200\u0026deg;C, 200\u0026ndash;450\u0026deg;C, and above 450\u0026deg;C are attributed to weak, moderate, and strong acidic sites, respectively [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Upon the addition of copper to the YZ support, the weakly acidic sites gradually diminished owing to the copper coverage. This effect was more pronounced in the 15CYZ sample because the large CuO crystallites obstructed the acidic sites of YZ. Additionally, the presence of Cu introduced new catalytic sites, enhancing the overall efficiency of the catalytic process. As indicated in the table, increasing the Cu loading from 5 to 15CYZ results in a gradual decrease in the total acidity of the CYZ catalysts. The observed decrease in total acidity with increasing Cu loading can be attributed to the progressive coverage of YZ acidic sites by copper species. This trend suggests that the copper content plays a crucial role in modulating the surface acidity of the CYZ catalysts. Furthermore, the introduction of new catalytic sites by Cu incorporation may compensate for the loss of acidity, potentially leading to a more balanced and efficient catalytic performance.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eScanning electron microscopy (SEM) was employed to investigate the morphology of the zeolite samples. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e displays SEM images of both Y-zeolite and Cu-containing Y-zeolites. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea presents typical micrographs of microcrystalline zeolite Y, where a significant crystal size of about 1.0 \u0026micro;m is noticeable. Figure\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e illustrates the distribution maps of Al, Si, and Cu on the surface of the 5CuYZ catalyst. The mapping image of Cu (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e) reveals that it was uniformly distributed across the 5CuYZ support. This even distribution of copper suggests an effective dispersion of the active metal on the YZ surface, which is vital for catalytic performance. Such a consistent distribution likely enhances the accessibility of reactants to the active sites. The uniform copper distribution on the zeolite surface indicates a high level of metal dispersion, which is essential for maximizing catalytic activity. This even spread of active sites can result in increased reaction rates and improved overall catalytic efficiencies. Additionally, the well-dispersed copper particles may contribute to the catalyst's enhanced stability during extended use.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eTransmission electron microscopy (TEM) was employed to examine the microstructure of 5CYZ and the distribution of copper. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e, the entire YZ maintains a consistent structure, aligning with the results from SEM. The copper particles appear to be uniformly dispersed throughout the YZ matrix, with no visible agglomeration or clustering. This homogeneous distribution of copper suggests effective incorporation during the synthesis process.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe acidic characteristics of the Cu-containing Y-zeolite were evaluated by quantitative IR analysis of pyridine adsorption, as depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e. This highly basic molecule is commonly employed to identify the types and numbers of Br\u0026oslash;nsted and Lewis acid sites in solid catalysts. When pyridine interacts with Br\u0026oslash;nsted sites, it receives a proton, forming pyridinium ions, which are detected by the bands at 1550\u0026ndash;1540 cm\u003csup\u003e-1\u003c/sup\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Conversely, Lewis acid sites, which accept electron pairs, coordinate with pyridine, resulting in PyL bands in the 1460\u0026ndash;1430 cm\u003csup\u003e-1\u003c/sup\u003e range[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. The position of the PyL band indicates the strength of the Lewis sites; a higher position indicates a greater number of electron acceptors. The IR spectra of pyridine adsorbed on the Cu-containing Y-zeolite samples revealed both the Br\u0026oslash;nsted and Lewis acid sites. The intensity of the PyL band at 1452 cm\u003csup\u003e-1\u003c/sup\u003e increased with increasing copper content, signifying an increase in Lewis acidity. These findings suggest that incorporation of Cu into the zeolite structure enhanced the number of Lewis acid sites, potentially affecting the catalytic behavior of the material. Interestingly, as the copper content in the Y-zeolite increased, there was an increase in Lewis acid sites, accompanied by a decrease in the number of Bronsted acid sites. This phenomenon can be attributed to the replacement of protons in the zeolite framework by copper ions during the preparation process, and the observed trade-off between Lewis and Br\u0026oslash;nsted acidities with increasing copper content has significant implications for the catalytic properties of Cu-containing Y-zeolites. This balance between the acid site types can be fine-tuned by adjusting the copper loading, allowing for the optimization of the catalytic performance in specific reactions. Furthermore, the ability to control the acid-site distribution opens up possibilities for tailoring these materials for a wide range of applications in heterogeneous catalysis.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe size of the copper particles was evaluated through N\u003csub\u003e2\u003c/sub\u003eO decomposition. As indicated in Table\u0026nbsp;2, the particle size grew with an increase in Cu loading. This observation is supported by XRD and SEM analyses, which suggest that the larger particle size at higher copper loadings is due to greater agglomeration during synthesis. This agglomeration could influence the catalytic performance of copper particles, possibly diminishing their total surface area and active sites.\u003c/p\u003e\u003cp\u003eTable.2: N\u003csub\u003e2\u003c/sub\u003eO decomposition measurements results of various CYZ catalysts\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabc\" border=\"1\"\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCatalyst\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCrystallite size\u003csup\u003ea\u003c/sup\u003e(nm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eH\u003csub\u003e2\u003c/sub\u003e 2nd uptake\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e(mole/g)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eParticle size\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\u003cp\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\u003eYZ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5CYZ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.012\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e10CYZ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.008\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e10.2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e15CYZ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e19.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.004\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e22.3\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\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003ea-XRD, b- N\u003csub\u003e2\u003c/sub\u003eO decomposition studies\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Catalytic activity:\u003c/h2\u003e\u003cp\u003eAs illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e, we explored the impact of varying the metal loading on the catalytic performance in the hydrogenation of GVL using different CYZ catalysts. Several products were generated during this process, including 2-methyltetrahydrofuran, 1,4 pentanediol, pentenoic acid, valeric acid, 1-pentanol, and 2-pentanol, with MTHF and PDO as the primary products. The formation of these various products underscores the complexity of the GVL hydrogenation process. Optimizing the yield of the desired products, especially MTHF and PDO, requires careful control of the reaction conditions and catalyst selection. The conversion of γ-valerolactone (GVL) to methyl tetrahydrofuran (MTHF) involves a series of reactions including hydrogenation and dehydration. Initially, the carbonyl group in GVL is hydrogenated to form a 2-hydroxymethyltetrahydrofuran intermediate. This intermediate was further hydrogenated to 5-hydroxy pentanone, which was then hydrogenated to produce PDO. Finally, PDO undergoes cyclisation to form the target compound, methyl tetrahydrofuran. The transformation of GVL to MTHF is intricate, necessitating precise control of the reaction conditions and catalysts to achieve a high selectivity and yield. The other products resulted from over-hydrogenation. The choice of the catalyst is crucial for determining the efficiency and specificity of each step in the reaction sequence. The figure shows that the Bare YZ support was inactive for GVL hydrogenation. However, when copper was loaded onto YZ, the activity significantly increased from 4.0\u0026ndash;92.1%, indicating the vital role of copper in the conversion of GVL to MTHF. Under ambient pressure and a reaction temperature of 250\u0026deg;C, the GVL conversion decreased from 92.1\u0026ndash;69.4% as the Cu loading increased from 5 to 15 wt. %, with selectivity also decreasing from 92.1 to 69.4%. It was demonstrated that 5CYZ achieved the best and most optimized GVL conversion and MTHF selectivity of 92.1% and 84%, respectively. The high diffusivity of copper in YZ allows it to exhibit maximum catalytic activity owing to its superior Cu dispersion, smaller particle sizes, and strong acidic site availability. Temperature and pressure during the reaction are critical parameters that significantly influence the reaction kinetics and product distribution in the hydrogenation process. The enhanced dispersion of Cu particles and strong acidic sites on the support surface was attributed to the synergistic effect of Cu and YZ on the catalyst surface, suggesting that an optimal balance between metal loading and the catalyst support is crucial for maximizing GVL conversion and MTHF selectivity. Higher copper loadings of more than 5 wt. % appear to have a detrimental effect on catalytic performance, possibly due to reduced dispersion or blockage of active sites. Further investigation of the relationship between copper loading, particle size distribution, and acid site density could provide valuable insights for catalyst optimization in this reaction system. In the Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e, it is evident that the size of the copper particles affects the MTHF yield. As the particle size increases from 5.1 to 19.7 nm, there is a gradual decrease in the MTHF yield. This trend suggests that smaller copper particles are more effective catalysts for the production of MTHF. The increased surface area-to-volume ratio of smaller particles likely provides more active sites for the reaction to occur. Further investigation into the optimal particle size range could lead to improved catalyst design and enhanced MTHF yields in industrial applications.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eReaction conditions: 10% GVL, 0.3g catalyst, 0.5ml/hour, 250\u0026deg;C and 0.1MPa hydrogen pressure.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThis study examined how varying reaction temperature affects the catalytic performance of GVL hydrogenation using a 5CYZ catalyst, with temperatures between 200\u0026ndash;300\u0026deg;C and hydrogen pressure of 0.1MPa, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e. As temperature increased from 200 to 300\u0026deg;C, GVL conversion increased from 53.2\u0026ndash;100%, whereas MTHF selectivity declined from 89.1\u0026ndash;72.5%. Complete GVL conversion was achieved at 275\u0026deg;C. At lower temperatures (200\u0026ndash;225\u0026deg;C), GVL conversion was low but MTHF selectivity remained high. When temperature reached 275\u0026deg;C, GVL conversion improved to nearly 100%, and selectivity shifted towards PDO production. Results demonstrate that temperature plays a crucial role in GVL conversion and product selectivity. Increasing temperature beyond optimal conditions could lead to undesirable side reactions or decreased MTHF selectivity. The optimal reaction temperature appears to be around 250\u0026ndash;275\u0026deg;C, balancing high GVL conversion with good MTHF selectivity. Above 275\u0026deg;C, side reactions likely become more prevalent, leading to decreased MTHF selectivity and increased formation of byproducts. These results demonstrate the importance of carefully controlling reaction temperature to maximize desired product yields in GVL hydrogenation using the 5CYZ catalyst.\"The optimal reaction conditions were 250\u0026deg;C and ambient pressure, providing the best balance between GVL conversion and MTHF selectivity. These findings suggest temperature optimization is crucial for achieving desired balance between GVL conversion and product selectivity. At 250\u0026deg;C, the catalyst showed optimal performance with high GVL conversion and favorable MTHF selectivity. Further research could explore fine-tuning reaction conditions or modifying catalyst composition to enhance MTHF selectivity at higher temperatures.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eReaction conditions: 10% GVL, 0.3g catalyst, 0.5ml/hour and 0.1Ma hydrogen pressure.\u003c/p\u003e\u003cp\u003eThe impact of GVL loading on the 5CYZ catalyst's performance was evaluated (Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e). As the GVL loading increased from 0.5 to 1.5 ml/hour, both GVL conversion and MTHF selectivity consistently decreased. This decline was due to the blockage of active sites by reactant molecules. Therefore, it was concluded that a GVL loading of 0.5 ml/hour is optimal for further studies. This rate was deemed ideal for efficient conversion while minimizing the obstruction of active sites, and optimizing GVL loading is essential for maintaining catalyst efficiency and maximizing product yield.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e13\u003c/span\u003e illustrates the impact of catalyst quantities on GVL hydrogenation to MTHF at 250\u0026deg;C. Doubling the catalyst from 0.2 g to 0.4 g improved both LA conversion and GVL yield. The highest GVL conversion, with 74.5% selectivity for MTHF, was achieved using 0.5 g of 5CZ, indicating insufficient active sites for complete hydrogenation to MTHF. When the catalyst was adjusted to between 0.3 g and 0.4 g, decreased MTHF selectivity was observed, suggesting 0.3 g provided adequate catalytic sites for converting GVL to MTHF. Increasing catalyst to 0.3 g and 0.4 g caused a slight decline in MTHF selectivity, possibly due to over-hydrogenation or side reactions. This finding shows the importance of optimizing catalyst loading to balance conversion and selectivity. Using 0.3 g of catalyst offers the best performance, maximizing MTHF yield while minimizing unwanted byproducts.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAdditionally, it is crucial to investigate the long-term durability and reusability of the 5CYZ catalyst for its potential application in sustainable biofuel production on an industrial scale, as illustrated in the TOS graph in Fig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e14\u003c/span\u003e. The catalyst's stability was evaluated over a 12-hour duration, maintaining an optimal GVL loading rate of 0.5 ml/hour, a reaction temperature of 250\u0026deg;C, and an H\u003csub\u003e2\u003c/sub\u003e pressure of 0.1MPa. Throughout this period, the 5CYZ catalyst exhibited remarkable stability, consistently achieving GVL conversion and MTHF selectivity. This sustained stability suggests that the 5CYZ catalyst is a strong candidate for industrial applications in converting GVL to MTHF. The catalyst's performance remained consistent, with no significant decrease in activity or selectivity observed over the extended reaction period. This stability can be attributed to the robust structure and composition of the 5CYZ catalyst, which effectively resists deactivation under the given reaction conditions.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAccording to the literature, all catalysts mentioned showed enhanced activity when subjected to high-pressure environments. Notably, the 5CYZ catalyst exhibited the best catalytic performance, achieving a GVL conversion rate of % and MTHF selectivity of 82% at 250\u0026deg;C under atmospheric H\u003csub\u003e2\u003c/sub\u003e pressure (Fig.\u0026nbsp;\u003cspan refid=\"Fig15\" class=\"InternalRef\"\u003e15\u003c/span\u003e). The exceptional performance of the 5CZ catalyst was due to its distinctive structural characteristics and improved Cu dispersion. The exceptional catalytic performance of the 5CYZ catalyst, achieving a high GVL conversion rate and MTHF selectivity at 250\u0026deg;C under atmospheric H\u003csub\u003e2\u003c/sub\u003e pressure, suggests that its smaller particle size plays a crucial role. The improved Cu dispersion likely contributes to a larger active surface area, allowing for more efficient catalytic reactions. The ability of the catalyst to maintain a high selectivity towards MTHF indicates that it effectively promotes the desired reaction pathway while minimizing unwanted side reactions. Further investigation of the specific structural features and surface properties of the 5CYZ catalyst could provide valuable insights for the development of more efficient catalysts for similar applications.\u003c/p\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eThis study investigates the vapor-phase hydrogenation of GVL to MTHF at atmospheric pressure using copper oxide supported on YZ. The YZ catalyst with copper was prepared via the impregnation method and analyzed using XRD, UV-DRS, TPD-NH3, ICP, BET, TPR-H\u003csub\u003e2\u003c/sub\u003e, XPS, SEM, and TEM. When GVL was hydrogenated with the 5CYZ catalyst at 250\u0026deg;C and 0.1Mpa, a GVL conversion rate of 92.1% and an MTHF selectivity of 84% were obtained. The improved dispersion of the Cu particles and the presence of strong acidic sites on the support surface were attributed to the synergistic interaction between Cu and YZ in the 5CYZ catalyst. Over a 12-hour duration, the 5CYZ catalyst exhibited remarkable stability, maintaining consistent GVL conversion and MTHF selectivity. This long-term stability suggests that the 5CYZ catalyst is promising for industrial applications in the conversion of GVL to MTHF. This study contributes to the growing body of knowledge in green chemistry processes, could lead to more efficient and environmentally friendly production of valuable chemicals from renewable resources, and has significant implications for the development of sustainable chemical processes. The high conversion rate and selectivity achieved with the 5CYZ catalyst demonstrated its potential for the efficient production of MTHF from GVL.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eFunding\u003c/h2\u003e\u003cp\u003eThis project did not receive any external funding or additional grants.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e\u003cp\u003eThe all authors thanks to Department of Chemistry, CVR College of Engineering Hyderabad, India. CRCL, New Delhi, India, G. Narayanamma Institute of Technology and Sciences, Hyderabad, India. Department of Chemistry, Chaitanya Bharathi Institute of Technology, Hyderabad, India. Department of Chemistry, University College of Science Hyderabad, India\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eKhawaja, A.S., Zaheer, M.A., Ahmad, A., Mirani, A.A., Ali, Z., Advances in limitations and opportunities of clean biofuel production to promote decarbonization, Fuel. 342, 127662 (2023). https://doi.org/10.1016/j.fuel.2023.127662.\u003c/li\u003e\n\u003cli\u003eStancin, H., Mikulcic, H., Wang, X., Duic, N., A review on alternative fuels in future energy system, Renew. Sustain. Energy Rev. 128, 109927 (2020). https://doi.org/10.1016/j.rser.2020.109927.\u003c/li\u003e\n\u003cli\u003eSun, P.T., Peng, H., Valorisation of Biomass Waste for Sustainable Bioenergy and Biofuel Production, Bioengineering. 10, 4 (2023). https://doi.org/10.3390/bioengineering10050619.\u003c/li\u003e\n\u003cli\u003eMignogna, D., Szabo, M., Ceci, P., Avino, P., Biomass Energy and Biofuels: Perspective, Potentials, and Challenges in the Energy Transition, Sustain. 16, 1 (2024). https://doi.org/10.3390/su16167036.\u003c/li\u003e\n\u003cli\u003eOumer, A.N., Hasan, M.M., Baheta, A.T., Mamat, R., Abdullah, A.A., Bio-based liquid fuels as a source of renewable energy: A review, Renew. Sustain. Energy Rev. 88, 82 (2018). https://doi.org/10.1016/j.rser.2018.02.022.\u003c/li\u003e\n\u003cli\u003eKhalid, M., Granollers Mesa, M., Scapens, D., Osatiashtiani, A., Advances in Sustainable \u0026gamma;-Valerolactone (GVL) Production via Catalytic Transfer Hydrogenation of Levulinic Acid and Its Esters, ACS Sustain. Chem. Eng. (2024). https://doi.org/10.1021/acssuschemeng.4c05812.\u003c/li\u003e\n\u003cli\u003ePonnala, B., Rajendiran, R., Vijayanand P., Selvaraj, M., Rokhum, S.L., Balla, P., Kim, S., Engineering acidic and Pt sites on WO\u003csub\u003e3\u003c/sub\u003e- doped H-mordenite supported Pt catalyst for hydrogenation of \u0026gamma; -valerolactone to methyl tetra hydrofuran, Mol. Catal. 559 (2024) 114065. https://doi.org/10.1016/j.mcat.2024.114065.\u003c/li\u003e\n\u003cli\u003ePutrakumar, B., Kumar, S.P., Rao, G.S., Pethan Rajan, N., Bhanuchander, P., Raveendra, G., Vijayanand, P., Lassi, U., Bakhsh, E.M., S.B. Khan, S. Kim, Copper nanoparticles encapsulated in a nanoporous carbon-based catalyst in the upgradation of \u0026gamma;-valerolactone to 1,4-pentanediol by selective hydrogenation, Mater. Today Sustain. 22, 1000406 (2023). https://doi.org/10.1016/j.mtsust.2023.100406.\u003c/li\u003e\n\u003cli\u003eBanerjee, D., Sahu, A.K., Clegg, J.K., Upadhyayula, S., Recent advances in 2-methylfuran production via catalytic transfer hydrogenation of biomass-derived furfural, Chem. Eng. J. 493, 152552 (2024). https://doi.org/10.1016/j.cej.2024.152552.\u003c/li\u003e\n\u003cli\u003eRackemann, D.W., W.O. Doherty, The conversion of lignocellulosics to levulinic acid, Biofuels, Bioprod. Biorefining. 5 (2011) 198\u0026ndash;214. https://doi.org/10.1002/bbb.267.\u003c/li\u003e\n\u003cli\u003eHuerta-Rosas, B., Coronel-Mu\u0026ntilde;oz, M., Quiroz-Ram\u0026iacute;rez, J.J., C\u0026aacute;ceres-Barrera, C.R., Contreras-Zaraz\u0026uacute;a, G., Segovia-Hern\u0026aacute;ndez, J.G., S\u0026aacute;nchez-Ram\u0026iacute;rez, E., Intensified alternative for sustainable gamma-valerolactone production from levulinic acid, Chem. Eng. Res. Des. 217, 38 (2025). https://doi.org/10.1016/j.cherd.2025.03.023.\u003c/li\u003e\n\u003cli\u003eTuan Hoang, A, Viet Pham, V., 2-Methylfuran (MF) as a potential biofuel: A thorough review on the production pathway from biomass, combustion progress, and application in engines, Renew. Sustain. Energy Rev. 148,111 (2021) 111265. https://doi.org/10.1016/j.rser.2021.111265.\u003c/li\u003e\n\u003cli\u003eNaranov, E., Sustainable Production of Chemicals via Hydrotreating of CO\u003csub\u003e2\u003c/sub\u003e and Biomass Derived Molecules Using Heterogeneous Noble Metal Oxide Catalysts, ChemCatChem. 16, 1 (2024). https://doi.org/10.1002/cctc.202301268.\u003c/li\u003e\n\u003cli\u003eLiu, Z., Zhang, R., Liu, H., Zhang, J., Sun, Y., Li, N., Peng, L., Effect of carbon modifier on characteristics and catalytic properties of zeolite\u0026ndash;carbon hybrid supported Zr towards \u0026gamma;-valerolactone production, Fuel. 359, 130380 (2024). https://doi.org/10.1016/j.fuel.2023.130380.\u003c/li\u003e\n\u003cli\u003eZhang, G., Ma, L., Dong, Y., Fang, Y., Kong, X., Fabrication of hierarchical flower-like NiMo bimetallic catalyst for valorization of biomass platforms, Fuel. 333, 126400 (2023). https://doi.org/10.1016/j.fuel.2022.126400.\u003c/li\u003e\n\u003cli\u003eRuscher, C.H., Salman, N., Buhl, J.C, Lutz, W., Relation between growth-size and chemical composition of X and Y type zeolites, Microporous Mesoporous Mater. 92, 309 (2006). 10.1016/j.micromeso.2006.01.016\u003c/li\u003e\n\u003cli\u003eSenila, M., Cadar, O., Modification of natural zeolites and their applications for heavy metal removal from polluted environments: Challenges, recent advances, and perspectives, Heliyon. 10, 25303 (2024). https://doi.org/10.1016/j.heliyon.2024.e25303.\u003c/li\u003e\n\u003cli\u003eLang, Q., Lu, P., Yang, X., Valtchev, V., Zeolites for the environment, Green Carbon. 2, 12 (2024). https://doi.org/10.1016/j.greenca.2024.02.007.\u003c/li\u003e\n\u003cli\u003eFerrarelli, G., Migliori, M., Catizzone, E., Recent Trends in Tailoring External Acidity in Zeolites for Catalysis, ACS Omega. 9, 29072 (2024). https://doi.org/10.1021/acsomega.4c03899.\u003c/li\u003e\n\u003cli\u003eNarayanan, S., Tamizhdurai, P., Mangesh, V.L., Ragupathi, C., Santhana krishnan, P., Ramesh, A., Recent advances in the synthesis and applications of mordenite zeolite - review, RSC Adv. 11, 250 (2020). https://doi.org/10.1039/d0ra09434j.\u003c/li\u003e\n\u003cli\u003eJaniga, J., Investigation of phase purity of faujasite-type Y zeolite, Zeolites. 10, 38 (1990). https://doi.org/10.1016/0144-2449(90)90092-6.\u003c/li\u003e\n\u003cli\u003eBanerjee, S., Sarkar, S., Sarkar, S., Patra A.K., Rational design of self-assembled copper oxide nanoparticles into hierarchical nanorods with high-surface-area for environmental remediation of wastewater, Inorg. Chem. Commun. 160, 111925 (2024). https://doi.org/10.1016/j.inoche.2023.111925.\u003c/li\u003e\n\u003cli\u003eBalla, P., Seelam, P.K., Rajenidran, R., Balaga, R., Challa, P., Perupogu, V., Lassi, U., Sungtak, K., Selective hydrogenation of levulinic acid over a highly dispersed and stable copper particles embedded into the ordered mesoporous carbon supported catalyst, Catal. Commun. 178, 106673 (2023). https://doi.org/10.1016/j.catcom.2023.106673.\u003c/li\u003e\n\u003cli\u003eShoja Razavi, R., Loghman-Estarki, M.R., Synthesis and Characterizations of Copper Oxide Nanoparticles Within Zeolite Y, J. Clust. Sci. 23,1097 (2012). https://doi.org/10.1007/s10876-012-0502-y.\u003c/li\u003e\n\u003cli\u003eZhakypov, A.S., Nemkayeva, R.R., Yerlanuly, Y., Tulegenova, M.A., Kurbanov, B.Y., Aitzhanov, M.B., Markhabayeva, A.A., Gabdullin, M.T., Synthesis and in situ oxidation of copper micro- and nanoparticles by arc discharge plasma in liquid, Sci. Rep. 13, 1 (2023). https://doi.org/10.1038/s41598-023-41631-2.\u003c/li\u003e\n\u003cli\u003eSilva, M., Baltrus, J.P., Williams, C., Knopf, A., Zhang, L., Baltrusaitis, J., Heterogeneous photo-Fenton-like degradation of emerging pharmaceutical contaminants in wastewater using Cu-doped MgO nanoparticles, Appl. Catal. A Gen. 630, 118468 (2022). https://doi.org/10.1016/j.apcata.2021.118468.\u003c/li\u003e\n\u003cli\u003ePothu, R., Challa, P., Rajesh, R., Boddula, R., Balaga, R., Balla, P., Perugopu, V., Radwan, A.B., Abdullah, A.M., Al-Qahtani, N., Vapour-Phase Selective Hydrogenation of \u0026gamma;-Valerolactone to 2-Methyltetrahydrofuran Biofuel over Silica-Supported Copper Catalysts, Nanomaterials. 12, 12193414 (2022). https://doi.org/10.3390/nano12193414.\u003c/li\u003e\n\u003cli\u003eJabłońska, M., Gora-Marek, K., Bruzzese, P.C., A. Palčić, K. Pyra, K. Tarach, M. Bertmer, D. Poppitz, A. P\u0026ouml;ppl, R. Gl\u0026auml;ser, Influence of Framework n(Si)/n(Al) Ratio on the Nature of Cu Species in Cu-ZSM-5 for NH\u003csub\u003e3\u003c/sub\u003e-SCR-DeNOx, ChemCatChem. 14, 627 (2022). https://doi.org/10.1002/cctc.202200627.\u003c/li\u003e\n\u003cli\u003eMitta, H., Seelam, P.K., Ojala, S., Keiski, R.L., Balla, P., Tuning Y-zeolite based catalyst with copper for enhanced activity and selectivity in vapor phase hydrogenolysis of glycerol to 1,2-propanediol, Appl. Catal. A Gen. 550, 308 (2018). https://doi.org/10.1016/j.apcata.2017.10.019.\u003c/li\u003e\n\u003cli\u003eUpare, P.P., Lee, J.M., Hwang, Y.K., Hwang, D.W., Lee, J.H., Halligudi, S.B., Hwang, J.S., Chang, J.S., Direct hydrocyclization of biomass-derived levulinic acid to 2-methyltetrahydrofuran over nanocomposite copper/silica catalysts, ChemSusChem. 4, 1749 (2011) 1749\u0026ndash;1752. https://doi.org/10.1002/cssc.201100380.\u003c/li\u003e\n\u003cli\u003eZheng, J., Zhu, J., Xu, X., Wang, W., Li, J., Zhao, Y., Tang, K., Song, Q., Qi, X., Kong, D., Tang, Y., Continuous hydrogenation of ethyl levulinate to \u0026gamma;-valerolactone and 2-methyl tetrahydrofuran over alumina doped Cu/SiO\u003csub\u003e2\u003c/sub\u003e catalyst: The potential of commercialization, Sci. Rep. 6, 28898 (2016). https://doi.org/10.1038/srep28898.\u003c/li\u003e\n\u003cli\u003eNovod\u0026aacute;rszki, G., Solt, H.E.,Valyon, J., L\u0026oacute;nyi, F., Hancs\u0026oacute;k, J., Deka, D., Tuba, R., Mih\u0026aacute;lyi, M.R., Selective hydroconversion of levulinic acid to \u0026gamma;-valerolactone or 2-methyltetrahydrofuran over silica-supported cobalt catalysts, Catal. Sci. Technol. 9,2291 (2019). https://doi.org/10.1039/c9cy00168a.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"waste-and-biomass-valorization","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"wave","sideBox":"Learn more about [Waste and Biomass Valorization](http://link.springer.com/journal/12649)","snPcode":"12649","submissionUrl":"https://submission.nature.com/new-submission/12649/3","title":"Waste and Biomass Valorization","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Y-zeolite, copper, γ-valerolactone, methyltetrahydrofuran","lastPublishedDoi":"10.21203/rs.3.rs-6865530/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6865530/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA sustainable approach to chemistry is achieved by utilizing heterogeneous catalysts for the synthesis of chemicals derived from biomass. Using impregnation, Cu/Y-Zeolite catalysts were prepared in this work for hydrogenating γ-valerolactone (GVL) to methyl tetrahydrofuran (MTHF). X-ray diffraction (XRD), Temperature programmed reduction (TPR-H\u003csub\u003e2\u003c/sub\u003e), Temperature programmed desorption (TPD-NH\u003csub\u003e3\u003c/sub\u003e), UV-DRS, and HR-TEM were used for characterization of the synthesized catalysts in terms of their structure, surface, electronic and spectroscopic attributes. The Lewis and Bronsted acidity further confirmed by Py-IR spectroscopy. The N\u003csub\u003e2\u003c/sub\u003eO decomposition studies reveals the copper surface area and copper particle size. When GVL was hydrogenated using a 5CYZ catalyst at a temperature of 250\u0026deg;C and a hydrogen pressure of 0.1MPa, the GVL conversion rate reached 92.1%, and the selectivity for MTHF was 84%. To achieve optimal conversion of GVL to MTHF with high selectivity, reaction conditions such as temperature, GVL input rate, and catalyst amount were fine-tuned.\u003c/p\u003e","manuscriptTitle":"Engineering Cu Supported Y-Zeolite Catalysts for the Selective Conversion of γ-Valerolactone to Methyl Tetrahydrofuran","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-11 08:18:50","doi":"10.21203/rs.3.rs-6865530/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2025-07-07T03:43:35+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-06T16:10:32+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Waste and Biomass Valorization","date":"2025-06-29T16:03:26+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-11T06:23:40+00:00","index":"","fulltext":""},{"type":"submitted","content":"Waste and Biomass Valorization","date":"2025-06-10T14:00:51+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"waste-and-biomass-valorization","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"wave","sideBox":"Learn more about [Waste and Biomass Valorization](http://link.springer.com/journal/12649)","snPcode":"12649","submissionUrl":"https://submission.nature.com/new-submission/12649/3","title":"Waste and Biomass Valorization","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"a300c861-c7ca-4617-bcdc-4e922d6c3e01","owner":[],"postedDate":"July 11th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-22T16:11:58+00:00","versionOfRecord":{"articleIdentity":"rs-6865530","link":"https://doi.org/10.1007/s12649-025-03436-4","journal":{"identity":"waste-and-biomass-valorization","isVorOnly":false,"title":"Waste and Biomass Valorization"},"publishedOn":"2025-12-16 15:58:09","publishedOnDateReadable":"December 16th, 2025"},"versionCreatedAt":"2025-07-11 08:18:50","video":"","vorDoi":"10.1007/s12649-025-03436-4","vorDoiUrl":"https://doi.org/10.1007/s12649-025-03436-4","workflowStages":[]},"version":"v1","identity":"rs-6865530","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6865530","identity":"rs-6865530","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}