Oxide Catalysts Research Articles

Exploring the joint influence of SO2 and alkali metal on FeW mixed oxides catalyst for NOx elimination

The coexistence of multiple substances in the flue gas, such as alkali metal and SO2, results in the NH3-SCR catalysts suffering from serious deactivation. Therefore, we systematically studied the effects of coexisting SO2 and Na on the FeW oxides for NOx elimination. This study elucidates that the joint influence mechanism of these substances on SCR activity was regulated by reaction temperatures. When the temperature was below 300oC, the catalyst suffered a double whammy. The addition of SO2 in process of NH3-SCR resulted in a decrease in the activity of Na-poisoned FeW catalyst. It was largely due to the formation of inorganic SO42-, which not only consumed the NH3 but also blocked active sites. With the increase of reaction temperatures above 300oC, the SO2 could interact with Na2O to construct a ternary electron interaction of SO42--Na+-FeW, contributing to the improvement of alkali metal resistance. This sulfate adjusted the D-band center energy of the catalyst closer to the Fermi level, thereby boosting the adsorption energies of NH3 and NO, increasing their adsorption abilities. Furthermore, sulfate binding broke the Na-O-Fe and Na-O-W bonds, resulting in the restoration of Fe-O-W and Fe-O-Fe active sites and accumulation of Na+ species. Precise characterizations and theoretical calculations shed light on the joint mechanism of SO2 and alkali metals which provide guidance to the design SCR catalyst with excellent resistance to SO2 and alkali metal poisoning.

Ba-leaching-initiated structural destabilization of perovskite Ruthenates during the oxygen evolution reaction

The destabilization of a lattice structure during the oxygen evolution reaction (OER) is one of the most essential aspects for designing and realizing highly efficient electrocatalysts. However, the underlying mechanism of structural evolution or degradation at the microscopic scale on the electrocatalyst surface during the OER has not been elucidated because of the sluggish yet dynamic character of the reaction. To address this issue, the direct observation of the unstable electrocatalytic activity is necessary. In this study, we demonstrate that the structural destabilization of epitaxial cubic perovskite BaRuO3 thin films during the OER originates from Ba leaching, Ru dissolution, and oxygen vacancy. A thin film geometry is adopted to selectively visualize the structural decomposition at the well-defined sample surface. The cubic BaRuO3 thin film initially exhibits high OER activity, which drastically decreases even during the first cyclic voltammetry cycle and is completely lost after the first cycle. The OER activity loss is closely related to the generation of structural defects on the surface, indicating the absence of the Ba and Ru atoms. This study proposes the mechanism underlying the OER activity that can be extended to elucidate the structural destabilization in various Ru- and Ir-based oxide catalysts.

Influence of Oxygen Vacancies in La0.4Sr0.6FeO3-δ Perovskite Oxide Nanoparticles for the Oxygen Evolution Reaction

Oxygen vacancies are important factors to tune the performance of oxide catalysts for the oxygen evolution reaction (OER). However, it remains challenging how to control the concentration of the oxygen vacancies and decouple their effects on OER from other factors. In this work, we use a specific composition/phase La0.4Sr0.6FeO3- d perovskite oxide as an example to tailor the oxygen vacancies of their nanoparticulate using a modified molten salt synthesis and ozone treatment. The OER performance of the resulting La0.4Sr0.6FeO3- d nanoparticles with different degree of oxygen vacancies ranging from 0 to 25% are compared. The OER reactivity increases with increased oxygen vacancies in the materials, but the change is nonlinear. The OER stability, on the other hand, has a bimodal distribution. The activities of fully oxidized sample and the most oxygen-deficient sample degrade slower than the two samples in the middle. The results suggest that it is feasible to design catalysts with oxygen vacancy to be the most OER active and stable. Further investigation into the oxygen vacancy – active site relation would offer guiding principle to design and synthesize high OER performance oxide catalysts.

Supporting Nano Catalysts for the Selective Hydrogenation of Biomass-derived Compounds.

The selective hydrogenation of biomass derivatives presents a promising pathway for the production of high-value chemicals and fuels, thereby reducing reliance on traditional petrochemical industries. Recent strides in catalyst nanostructure engineering, achieved through tailored support properties, have significantly enhanced the hydrogenation performance in biomass upgrading. A comprehensive understanding of biomass selective upgrading reactions and the current advancement in supported catalysts is crucial for guiding future processes in renewable biomass. This review aims to summarize the development of supported nanocatalysts for the selective hydrogenation of the US DOE's biomass platform compounds derivatives into valuable upgraded molecules. The discussion includes an exploration of the reaction mechanisms and conditions in catalytic transfer hydrogenation (CTH) and high-pressure hydrogenation. By thoroughly examining the tailoring of supports, such as metal oxide catalysts and porous materials, in nano-supported catalysts, we elucidate the promoting role of nanostructure engineering in biomass hydrogenation. This endeavor seeks to establish a robust theoretical foundation for the fabrication of highly efficient catalysts. Furthermore, the review proposes prospects in the field of biomass utilization and address application bottlenecks and industrial challenges associated with the large-scale utilization of biomass.

Improving the Rechargeable Li-CO2 Battery Performances by Tailoring Oxygen Defects on Li-Ni-Co-Mn Multi-Metal Oxide Catalysts Recycled from Spent Ternary Lithium-Ion Batteries.

Rechargeable Li-CO2 batteries are considered as a promising carbon-neutral energy storage technology owing to their ultra-high energy density and efficient CO2 capture capability. However, the sluggish CO2 reduction/evolution kinetics impedes their practical application, which leads to huge overpotentials and poor cyclability. Multi-element transit metal oxides (TMOs) are demonstrated as effective cathodic catalysts for Li-CO2 batteries. But there are no reports on the integration of defect engineering on multi-element TMOs. Herein, the oxygen vacancy-bearing Li-Ni-Co-Mn multi-oxide (Re-NCM-H3) catalyst with the α-NaFeO2-type structure is first fabricated by annealing the NiCoMn precursor that derived from spent ternary LiNi0.8Co0.1Mn0.1O2 cathode, in H2 at 300°C. As demonstrated by experimental results and theory calculations, the introduction of moderate oxygen vacancy has optimized electronic state near the Fermi level (Ef), eventually improving CO2 adsorption and charge transfer. Therefore, the Li-CO2 batteries with Re-NCM-H3 catalyst deliver a high capacity (11808.9 mAh g-1), a lower overpotential (1.54V), as well as excellent stability over 216 cycles at 100mA g-1 and 165 cycles at 400mA g-1. This study not only opens up a sustainable application of spent ternary cathode, but also validates the potential of multi-element TMO catalysts with oxygen defects for high-efficiency Li-CO2 batteries.

Synergy between Fe-Co oxide catalysts supported over HZSM-5 for direct conversion of methane to methanol

The direct conversion of methane to methanol over iron and cobalt oxide based composite catalysts supported over HZSM-5 was carried out in a fixed-bed micro reactor under changing process parameters and catalyst compositions. The prepared catalysts were well characterized by various techniques including N2 adsorption desorption, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), pyridine FTIR, X-ray photoelectron spectroscopy (XPS), UV–vis spectroscopy and temperature programmed reduction (H2-TPR). The characterization results revealed the presence of various reducible iron and cobalt oxide species depending on the Fe/Co molar ratio and total metal oxide loading. Moreover, the XPS and UV–vis spectroscopic results also confirmed the variation of Fe2+/Fe3+ and Co2+/Co3+ species depending on the Fe-Co molar ratio which had strong influence on the performance of the composite catalysts. It was found that the cobalt species favours the formaldehyde formation whereas the iron species promotes the formic acid formation in their respective pure supported oxide catalysts. However, the synergistic effect of iron and cobalt oxide in equimolar ratio in composite catalysts appeared as effective for achieving highest yield of methanol. The methanol selectivity was also influenced by the alteration of various studied process parameters. The higher reaction temperature favoured the overoxidation of methanol to CO2 whereas the methanol selectivity increased with increasing the methane to oxygen ratio. The lattice to adsorbed oxygen ratio also had strong influence on the activity of composite catalysts and methanol selectivity. The highest methanol yield of 1.87% was achieved at the methane conversion of 42.81 % with the 20Fe1Co1Z catalyst at 873 K reaction temperature with CH4/O2 ratio of 2:1 and WHSV of 1030 ml hr−1 gcat−1.

Unraveling Oxidation and Spin States of a Single Fe-Based Meso-Macroporous Silica Catalyst in Fenton-like Reaction by Magnetic Measurements

Unraveling Oxidation and Spin States of a Single Fe-Based Meso-Macroporous Silica Catalyst in Fenton-like Reaction by Magnetic Measurements

Multivariate Bayesian Optimization of CoO Nanoparticles for CO2 Hydrogenation Catalysis.

The hydrogenation of CO2 holds promise for transforming the production of renewable fuels and chemicals. However, the challenge lies in developing robust and selective catalysts for this process. Transition metal oxide catalysts, particularly cobalt oxide, have shown potential for CO2 hydrogenation, with performance heavily reliant on crystal phase and morphology. Achieving precise control over these catalyst attributes through colloidal nanoparticle synthesis could pave the way for catalyst and process advancement. Yet, navigating the complexities of colloidal nanoparticle syntheses, governed by numerous input variables, poses a significant challenge in systematically controlling resultant catalyst features. We present a multivariate Bayesian optimization, coupled with a data-driven classifier, to map the synthetic design space for colloidal CoO nanoparticles and simultaneously optimize them for multiple catalytically relevant features within a target crystalline phase. The optimized experimental conditions yielded small, phase-pure rock salt CoO nanoparticles of uniform size and shape. These optimized nanoparticles were then supported on SiO2 and assessed for thermocatalytic CO2 hydrogenation against larger, polydisperse CoO nanoparticles on SiO2 and a conventionally prepared catalyst. The optimized CoO/SiO2 catalyst consistently exhibited higher activity and CH4 selectivity (ca. 98%) across various pretreatment reduction temperatures as compared to the other catalysts. This remarkable performance was attributed to particle stability and consistent H* surface coverage, even after undergoing the highest temperature reduction, achieving a more stable catalytic species that resists sintering and carbon occlusion.

Perovskite Oxide Catalysts for Enhanced CO2 Reduction: Embroidering Surface Decoration with Ni and Cu Nanoparticles

The imperative reduction of carbon dioxide into valuable fuels stands as a crucial step in the transition towards a more sustainable energy system. Perovskite oxides, with their high compositional and property adjustability, emerge as promising catalysts for this purpose, whether employed independently or as a supporting matrix for other active metals. In this study, an A-site-deficient La0.9FeO3 perovskite underwent surface decoration with Ni, Cu or Ni + Cu via a citric acid-templated wet impregnation method. Following extensive characterization through XRD, N2 physisorption, H2-TPR, SEM-EDX, HAADF STEM-EDX mapping, CO2-TPD and XPS, the prepared powders underwent reduction under diluted H2 to yield metallic nanoparticles (NPs). The prepared catalysts were then evaluated for CO2 reduction in a CO2/H2 = 1/4 mixture. The deposition of Ni or Cu NPs on the perovskite support significantly enhanced the conversion of CO2, achieving a 50% conversion rate at 500 °C, albeit resulting in only CO as the final product. Notably, the catalyst featuring Ni-Cu co-deposition outperformed in the intermediate temperature range, exhibiting high selectivity for CH4 production around 350 °C. For this latter catalyst, a synergistic effect of the metal–support interaction was evidenced by H2-TPR and CO2-TPD experiments as well as a better nanoparticle dispersion. A remarkable stability in a 20 h time-span was also demonstrated for all catalysts, especially the one with Ni-Cu co-deposition.

Highly Dispersed Mn-Doped Ceria Supported on N-Doped Carbon Nanotubes for Enhanced Oxygen Reduction Reaction.

The weak adsorption of oxygen on transition metal oxide catalysts limits the improvement of their electrocatalytic oxygen reduction reaction (ORR) performance. Herein, a dopamine-assisted method is developed to prepare Mn-doped ceria supported on nitrogen-doped carbon nanotubes (Mn-Ce-NCNTs). The morphology, dispersion of Mn-doped ceria, composition, and oxygen vacancies of the as-prepared catalysts were analyzed using various technologies. The results show that Mn-doped ceria was formed and highly dispersed on NCNTs, on which oxygen vacancies are abundant. The as-prepared Mn-Ce-NCNTs exhibit a high ORR performance, on which the average electron transfer number is 3.86 and the current density is 24.4% higher than that of commercial 20 wt % Pt/C. The peak power density of Mn-Ce-NCNTs is 68.1 mW cm-2 at the current density of 138.9 mA cm-2 for a Zn-air battery, which is close to that of 20 wt % Pt/C (69.4 mW cm-2 at 106.1 mA cm-2). Density functional theory (DFT) calculations show that the oxygen vacancy formation energies of Mn-doped CeO2(111) and pure CeO2(111) are -0.55 and 2.14 eV, respectively. Meanwhile, compared with undoped CeO2(111) (-0.02 eV), Mn-doped CeO2(111) easily adsorbs oxygen with the oxygen adsorption energy of only -0.68 eV. This work provides insights into the synergetic effect of Mn-doped ceria for facilitating oxygen adsorption and enhancing ORR performance.

New method for the preparation of hierarchical nanotube K0.3xMnxCe1-xOδ catalysts and their excellent catalytic performance for soot combustion

A series of nanofibrous K-Mn-Ce composite oxide catalysts were prepared via a centrifugal spinning method for the first time, and their physicochemical properties were studied. The prepared K0.3xMnxCe1-xOδ metal oxide catalyst, which is a composite of CeO2 and cryptopotassium manganese-type K2-xMn8O16, exhibits a hierarchical nanotube structure with uniform nanoneedles on its surface. During the process of soot oxidation, CeO2 utilizes its unique oxygen storage and release capacity to supply oxygen species. Simultaneously, the excellent redox properties of K2-xMn8O16 effectively promote valence cycling of the active components and produce more active oxygen species. This synergistic effect effectively enhances the intrinsic activity of the catalysts. Among the prepared catalysts, K0.15Mn0.5Ce0.5Oδ exhibits the highest catalytic performance, with 10% (T10), 50% (T50), and 90% (T90) soot conversion temperatures of 267 °C, 309 °C, and 338 °C, respectively, and shows good stability and water and sulfur resistance. Based on their simple preparation, low cost, and good catalytic performance, K0.3xMnxCe1-xOδ composite metal oxide catalysts have good potential in catalytic soot combustion applications.

MOF-derived CuO@CB@CF cathode for O2 activation to generate ROSs for efficient electro-Fenton-catalysis

The generation of reactive radicals by molecular oxygen activation has become an important advanced oxidation technique. The combination of highly active carbon materials and stable transition metal oxides can activate molecular oxygen to produce hydrogen peroxide and further produce active free radicals at the same time, which is an efficient way for the removal of organic pollutants by heterogeneous electro-Fenton (HEF) system. In this study, a novel metal organic framework (MOF) derived CuO-carbon black-carbon felt (CuO@CB@CF) composite catalytic electrode has been prepared, which can generate H2O2 efficiently by selective O2 reduction through two-electron pathway with high pollutant removal efficiency. By optimizing the calcination temperature of MOF and loading capacity, the MOF-derived CuO@CB@CF has demonstrated excellent performance as a HEF catalytic electrode. Meanwhile, the effects of applied voltage, pH value, electrode area and aeration conditions have been studied. The excellent performance of MOF-derived CuO@CB@CF provides new insights into the removal of organic pollutants through electro-Fenton processes of transition metal oxide and carbon-based catalysts.

Aromatic rich biofuel production via catalytic co‐pyrolysis of paulownia wood and polypropylene waste

AbstractThermo‐catalytic co‐pyrolysis of paulownia wood and polypropylene mixture were carried out in a fixed bed horizontal reactor system. The biochar obtained from pyrolysis of paulownia wood was activated by steam at 700°C. Activated biochar supported magnesium oxide, nickel oxide and cobalt oxide catalysts were prepared by incipient miosture impregnation and were used to upgrade the bio‐oil. Catalytic pyrolysis reduced the amount of bio‐oil compared with non‐catalytic pyrolysis (59.5% of bio‐oil). The results indicate that the production of aromatic compounds increased from 40.35% to 65.93, 62.12 and 61.56% using Ni, Co and Mg catalysts, respectively. For all three catalysts, the production of furan compounds decreased. It was found that bio‐char based catalysts are suitable for use in the co‐pyrolysis process to improvement the biofuel production.

In situ and Operando Characterisation in the Preferential Oxidation of Carbon Monoxide over Base Metal Oxide Catalysts: A Review

Polymer electrolyte membrane fuel cells (PEMFCs) are the core technology of the steadily growing hydrogen (H2) economy as they can convert chemical energy, in the form of H2, to electrical energy. If the H2 is derived from (green) hydrocarbons, via steam reforming and the water‐gas‐shift reaction, then it would contain small amounts of carbon monoxide (CO, 0.5 – 2%), among other gases. CO poisons the platinum‐based anode catalyst in the PEMFC, and the current recommendation is to decrease its concentration to below 0.01% (or 100 ppm) in the H2‐rich PEMFC feed. The preferential oxidation of CO (CO‐PrOx) is a promising strategy for decreasing the CO concentration, and base metal oxide catalysts have shown great potential in this regard. However, such catalysts tend to undergo physicochemical changes that cause undesirable catalytic activity and selectivity changes. This review discusses the different base metal oxide catalysts that have been evaluated in CO‐PrOx, while paying special attention to the various in situ and operando techniques that have been used to monitor the physicochemical changes of such catalysts during operation. We conclude the review by highlighting the recent and possible future attempts of circumventing the undesired physicochemical changes of base metal oxides during CO‐PrOx.

Chemical bonding and electronic properties along Group 13 metal oxides

ContextThe present work provides a systematic theoretical analysis of the nature of the chemical bond in Al2O3, Ga2O3, and In2O3 group 13 cubic crystal structure metal oxides. The influence of the functional in the resulting band gap is assessed. The topological analysis of the electron density provides unambiguous information about the degree of ionicity along the group which is linearly correlated with the band gap values and with the cost of forming a single oxygen vacancy. Overall, this study offers a comprehensive insight into the electronic structure of metal oxides and their interrelations. This will help researchers to harness information effectively, boosting the development of novel metal oxide catalysts or innovative methodologies for their preparation.MethodsPeriodic density functional theory was used to predict the atomic structure of the materials of interest. Structure optimization was carried out using the PBE functional, using a plane wave basis set and the PAW representation of the atomic cores, using the VASP code. Next, the electronic properties were computed by carrying out single point calculations employing PBE, PBE + U functionals using VASP and also with PBE and the hybrid HSE06 functionals using the FHI-AIMS software. For the hybrid HSE06, the impact of the screening parameter, ω, and mixing parameter, α, on the calculated band gap has also been assessed.

Microcosmic insights into Hg0-SO2 interaction on CuFe2O4 catalyst

CuFe2O4 is considered as a very promising kind of catalysts for Hg0 oxidation in the industrial flue gas. The flue gas produced by solid-fuel combustion usually contains acid gas component SO2, which can exhibit the versatile effects on Hg0 oxidation. However, the effects of SO2 on Hg0 oxidation catalyzed by CuFe2O4 catalyst and its reaction mechanism remain elusive. Herein, the reaction mechanism governing the effects of SO2 on Hg0 oxidation was investigated via the Hg0 oxidation experiments and density functional theory (DFT) calculations. The experimental results show that the temperature change and SO2 presence can affect the Hg0 removal efficiency of CuFe2O4 catalyst. SO2 has a certain degree of inhibition effect on the Hg0 oxidation of CuFe2O4 catalyst. The inhibition effect of SO2 is relatively weak in the low temperature range of 50–150 °C, which is closely associated with the competitive adsorption between SO2 and Hg0. SO2 exhibits a relatively strong inhibition effect on Hg0 oxidation in the high temperature range of 200–350 °C, which is related to the high-temperature sulfation of CuFe2O4 catalyst surface. Mercury species on the CuFe2O4 catalyst surface mainly exists in the forms of HgSO4 and HgO in the presence of SO2. The DFT-calculation results indicate that the conversion process of SO2 to SO3 includes two steps: SO2 adsorption and SO2 oxidation. The activation energy barrier of SO2 oxidation reaction is 216.42 kJ/mol. The oxidation of Hg0 on the surface of CuFe2O4 catalyst includes four steps: Hg0 adsorption, Hg* oxidation into HgO*, HgO*-to-HgSO4* conversion and HgSO4 desorption. HgSO4 is formed by the bimolecular reaction of HgO* and SO3* on CuFe2O4 catalyst. Hg* oxidation into HgO* is found to be the rate-determining step of HgSO4 formation.

Enhanced catalytic degradation of amoxicillin by phyto-mediated synthesised ZnO NPs and ZnO-rGO hybrid nanocomposite: Assessment of antioxidant activity, adsorption, and thermodynamic analysis

Abstract Antibiotics are resistant compounds that become emerging contaminants that cause hazards to human health and the ecological environment due to their wide production and consumption. The present research reveals the remediation of amoxicillin (AMX) antibiotic by catalytic degradation using fabricated zinc oxide (ZnO) and zinc oxide-reduced graphene oxide (ZnO-rGO) catalysts. The characterization of the catalyst was carried out via UV–Vis spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, and scanning electron microscopy to evaluate the morphology and composition of synthesised catalyst. The catalytic ability of ZnO-rGO and ZnO was investigated by analysing the degradation of AMX. The ZnO-rGO nanocomposites (NCs) showed improved catalytic performance towards AMX degradation (96%) than pure ZnO nanoparticles (85%), which may be attributed to the incorporation of rGO, which enhanced the adsorption rate and changed the electron–hole recombination rate. The antioxidant potential of synthesised nanomaterials was also analysed by three different methods. The adsorption behaviour was explained through the Langmuir and Freundlich models, and the results revealed that AMX adsorption followed the Freundlich model more closely for both catalysts. The adsorption of AMX was also studied thermodynamically at different temperatures. The negative Gibbs energy change, positive enthalpy change, and entropy change showed the reaction’s spontaneity and endothermic nature. Finally, it can be assumed that the ZnO-rGO NCs could be an effective semiconductor for the degradation of AMX from wastewater.

Regulating Cu Oxidation State for Electrocatalytic CO2 Conversion into CO with Near-Unity Selectivity via Oxygen Spillover.

Cu-based catalysts are the most intensively studied in the field of electrocatalytic CO2 reduction reaction (CO2RR), demonstrating the capacity to yield diverse C1 and C2+ products albeit with unsatisfactory selectivity. Manipulation of the oxidation state of Cu sites during CO2RR process proves advantageous in modulating the selectivity of productions, but poses a formidable challenge. Here, an oxygen spillover strategy is proposed to enhance the oxidation state of Cu during CO2RR by incorporating the oxygen donor Sb2O4. The Cu-Sb bimetallic oxide catalyst attains a remarkable CO2-to-CO selectivity approaching unity, in stark contrast to the diverse product distribution observed with bare CuO. The exceptional Faradaic efficiency of CO can be maintained across a wide range of potential windows of ≈700mV in 1m KOH, and remains independent of the Cu/Sb ratio (ranging from 0.1:1 to 10:1). Correlative calculations and experimental results reveal that oxygen spillover from Sb2O4 to Cu sites maintains the relatively high valence state of Cu during CO2RR, which diminishes the binding strength of *CO, thereby achieving heightened selectivity in CO production. These findings propose the role of oxygen spillover in CO2RR over Cu-based catalysts, and shed light on the rational design of highly selective CO2 reduction catalysts.

In situ surface etching strategy for bimetallic MOFs-derived oxides and their catalytic properties

MOFs and their derivatives are excellent carriers with large specific surface area. Here, we propose a new strategy to engineer a supported-Pt core shell MOF-derived metal oxide catalyst. In this work, ZnCo-glycol microspheres were used as sacrificial templates, and the pre-prepared Pt nanoparticles were modified in MOFs during the in situ surface etching strategy. Compared to the ZnCo-2MI-330 and ZnCo–Pt-330, ZnCo–Pt-2MI-330 presents good catalytic activity (T10 = 110 °C,T90 = 123 °C) and excellent stability on CO oxidation reaction. By detailed characterization, ZnCo–Pt-2MI-330 remains the original pore structure of MOFs and provides a larger specific surface area, while the addition of Pt NPs changes the content of active species (the high ratio of Co3+ and active oxygen species) in the metal oxides. More importantly, the strategy effectively improves the noble metal catalysts are apt to lose their activities during the thermal catalytic caused by the serious working environment.

Waste snail shells-derived mixed oxide catalyst for efficient transesterification of vegetable oil: Towards sustainable biodiesel production

This study explores the transesterification process of soybean oil for the production of biodiesel, utilizing an innovative mixed oxide catalyst obtained from discarded snail shells powder. The catalyst synthesis involved a thermal treatment at 900°C for 120 min, predominantly yielding calcium oxide (CaO). In order to evaluate its properties, we carried out a thorough characterization using various analytical techniques. The study explores the impact of crucial variables on the transesterification reaction, such as reaction time (from 30 to 150 min), methanol-to-oil ratio (from 3:1–18:1), and catalyst concentration (from 0.5% to 4% by weight). Optimal conditions emerged with a 90-min reaction time, a 12:1 methanol-to-oil ratio, and a 2% catalyst loading, yielding an impressive biodiesel conversion rate of approximately 93%. The validity of biodiesel conversion was confirmed through Fourier transform infrared spectroscopy (FTIR) and Proton Nuclear Magnetic Resonance Spectroscopy (1 H NMR). The resultant biodiesel exhibited highly favorable characteristics, including an acid value of 0.85 mg of KOH/g, a density of 886.8 kg/m3, and a viscosity of 4.6 mm2/s. These measurements align with the standards set forth in EN 14214 and ASTM D6751 regarding biodiesel quality. The utilization of waste snail shells powder as a precursor for synthesizing the mixed oxide catalyst presents a promising approach for the sustainable production of biodiesel from soybean oil, offering a sustainable and efficient approach to biofuel production.