Preparation Of Catalysts Research Articles

Synthesis and Characterisation of Graphene Oxide Catalysts for Glycerol Acetylation

Glycerol in large quantities as a by-product of biodiesel production is a promising feedstock to be converted into more valuable products such as acetin. In this work, acetin converted from glycerol acetylation with acetic acid was performed over graphene oxide as a catalyst in a batch reactor. The study's objective was to evaluate the effect of sodium nitrate amount in the catalyst preparation on the catalyst's characteristics and catalytic performance. The graphene oxide (GO) catalysts were charac­terised by various tests, such as SEM-EDX for their morphology, the nitrogen adsorption capacity using Breneur-Emmet Teller (BET), structural analysis using XRD, functional group us­­ing FTIR, and catalytic activity on glycerol acetylation. The GO1, GO2, and GO3 catalysts were varied based on the NaNO3 amount in the modified Hummer method. The experiments found that the NaNO3 amount in catalyst preparation plays a vital role in GO structure formation. The GO2 catalyst has the highest performance, as indicated by the highest surface area, pore volume, and size. High glycerol conversion (94 %) and selectivity toward the interest products of triacetin (24 %) and diacetin + triacetin (83 %) were reached in 2 h of reaction using three wt.% catalysts, 110 °C reaction temperature, and 1:9 molar ratio of glycerol to acetic acid. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Utilization of Cobalt and its Oxide/Hydroxide Mediated by Ionic Liquids/Deep Eutectic Solvents as Catalysts in Water Splitting.

With the ever-growing global demand for sustainable energy solutions, hydrogen has garnered significant attention as a clean, efficient, and renewable energy source. In the field of hydrogen production, catalyst research stands out as one of the foremost areas of focus. In recent years, the preparation of electrocatalysts using ionic liquids (ILs) and deep eutectic solvents (DESs) has attracted widespread attention. ILs and DESs possess unique physicochemical properties and are recognized as green media as well as functional materials. Cobalt-based catalysts have proven to be efficient electrocatalysts for water splitting. Incorporating ILs or DESs into the preparation of cobalt-based catalysts offers a remarkable advantage by allowing precise control over their structural design and composition. This control directly influences the adsorption properties of the catalyst's surface and the stability of reaction intermediates, thereby enabling enhanced control over reaction pathways and product selectivity. Consequently, the catalytic activity and stability of cobalt-based catalysts can be effectively improved. In the process of preparing cobalt-based catalysts, ILs and DESs can serve as solvents and templates. Owing to the good solubility of ILs and DESs, they can efficiently dissolve raw materials and provide a special nucleation and growth environment, obtaining catalysts with novel-structures. The main focus of this review is to provide a detailed introduction to metal cobalt and its oxide/hydroxide derivatives in the field of water splitting, with a particular emphasis on the research progress achieved through the utilization of IL and DES. The aim is to assist readers in designing and synthesizing novel and high-performance electrochemical catalysts.

Biodiesel from Crude Palm Oil: A Sustainable Development Strategy for Energy Security

The study investigates the synthesis process, catalyst preparation, and implications of CPO biodiesel production, focusing on energy security, environmental sustainability, and greenhouse gas emissions reduction. The study uses eggshell-derived calcium oxide (CaO) catalysts for catalyst preparation, demonstrating a novel approach to catalyst synthesis. Results show consistent biodiesel yields of 78.6%, demonstrating the efficiency of the synthesis process. The study also highlights the environmental benefits of CPO biodiesel production, including reduced carbon emissions and sustainable cultivation practices. The study emphasizes the potential of CPO biodiesel as a sustainable energy solution, paving the way for a cleaner, more resilient future.

Regulation of surface oxygen vacancy of Cu-CeO2/TiO2 heterostructures via fast Joule heating method for enhanced CO2 electrochemical reduction

Strict control of carbon emissions is crucial for expediting the achievement of carbon neutrality. However, the current CO2RR electrocatalytic exhibits numerous shortcomings that impede the enhancement of catalytic activity. Issues such as lengthy catalyst preparation times, and high levels of precious metal content. Additionally, the aggregation of ultrafine nanoparticles contributes to a rapid deterioration in catalytic performance. Herein, a Joule-heating method is efficiently utilized to synthesize heterostructures nano-catalysts for CO2 electroreduction on carbon cloth substrates. This method takes advantage of the thermoelectric coupling of the carbon cloth to achieve carbothermal reduction, while also regulating phase composition and introduction of oxygen vacancies. The Cu-CeO2/TiO2/CC catalyst synthesized in this method showed a current density in CO2 of −32 mA·cm−2 at −1.0 V (vs. RHE). Notably, this catalyst demonstrated high CO selectivity and Faraday efficiency (FECO) of up to 82.5 % at a low potential of −0.3 V (vs. RHE). Optimal electrochemical performance is achieved at a power of 40 W. The ultra-fast temperature change process prevented the agglomeration of catalyst particles and facilitated the construction of a stable heterogeneous interface with a high oxygen vacancy concentration. In conclusion, this study presents a promising approach, particularly for the rapid preparation of low-cost, highly selective non-precious metal electrocatalysts.

Catalytic Potential of Singgora Roof Tiles in Transesterification for Sustainable Biodiesel

The study centred around the uitilization of Singgora roof tiles as a heterogeneous catalyst in the production of biodiesel via the transesterification process. The motivation behind this choice stems from the non-recyclable nature of Singgora roof tiles and their potential applicability in biodiesel synthesis. To enhance the catalytic properties, zinc oxide (ZnO) is incorporated using the wet impregnation technique during catalyst preparation. The catalyst was characterized by XRF and SEM-EDX. A two-step transesterification method is employed to mitigate the levels of free fatty acid (FFA) in waste cooking oil (WCO). The initial step involves treating the WCO with sulfuric acid (H2SO4) to reduce FFA. Subsequently, the Singgora roof tiles catalyst is utilized in the second step. A high yield of FAMEs, specifically 96.96%, was achieved under the optimal conditions, which included a methanol-to- oil ratio of 12:1, a catalyst concentration of 1 wt.%, a reaction temperature of 65 °C, and a reaction time of 2 hours. The quality of the biodiesel produced was analyzed according to biodiesel standards such as ASTM D6751, EN 14214, and AOCS, and it met all the required standards. The study demonstrates the potential of using Singgora roof tiles as a heterogeneous catalyst in biodiesel production, offering a promising approach to repurposing non-recyclable materials and advancing sustainable biodiesel production methods.

A Comprehensive Review of Biodiesel Production using Heterogeneous Catalyst

Biodiesel, an eco-friendly alternative to petroleum diesel, is derived from vegetable oils or animal fats through transesterification. The use of heterogeneous catalysts, specifically titanium dioxide (TiO2) and calcium oxide (CaO), in biodiesel production has garnered significant attention due to their environmental benefits and potential to replace fossil fuels. This study systematically analyses biodiesel production using TiO2-CaO catalysts, highlighting their efficiency under various reaction conditions, catalyst preparation methods, and operational parameters. Different feedstocks, such as palm oil, cooking oils, and algal biomass, are evaluated. Methodologies reviewed include wet impregnation and photochemical techniques for catalyst synthesis, with varying reaction temperatures and times. The findings reveal that while TiO2 and CaO have been extensively researched, the variation in methodologies hinders the development of standardized procedures like XRD, SEM, BET, and thermal analysis. Results indicate that cooking oil is a cost-effective feedstock, yielding biodiesel efficiently under optimal conditions: a methanol-to-oil ratio of 24:1, catalyst concentration of 5%, and reaction temperatures of 55-65 °C. The highest biodiesel yield of 98% was achieved using palm oil. Further studies should focus on optimizing and standardizing biodiesel production processes using the TiO2-CaO catalyst.

The catalytic deoxygenation reaction temperature and N2 gas flow rate influence the conversion of soybean fatty acids into Green Diesel

BackgroundGreen diesel is a promising alternative as a petroleum replacement given the worldwide demand for petroleum fuel. Environmental issues have drawn public attention and concerns towards advancing renewable energy development. A catalytic deoxygenation (deCOx) was carried out to produce green diesel from soybean oil (SO) using a low-cost NiO-doped calcined dolomite (NiOCD) catalyst. MethodThe structure, chemical composition and morphology of NiOCD were comprehensively characterized by XRF, BET, TPD-CO2, SEM and TEM. In this study, the effect of two operating parameters, reaction temperature and flow rate of nitrogen, was discovered using a one-factor-at-a-time (OFAT) optimisation study. In addition, the life cycle cost analysis (LCCA) of stepwise catalyst preparation and green diesel production has been performed. Significant findingsAn optimal reaction temperature of 420 °C was found to provide the highest yield of green diesel (47.13 wt.%) with an 83.51% hydrocarbon composition. The ideal nitrogen flow rate, however, was found to be 50 cm3/min, which produced 41.80 wt.% of green diesel with an 88.63% hydrocarbon composition. The deoxygenation reaction was significantly impacted by both reaction temperature and nitrogen flow rate. According to LCCA, NiOCD catalyst has potential to lower the overall cost of producing green diesel compared to commercial zeolite catalysts.

Preparation of phosphorus-doped Cu-based catalysts by electrodeposition modulates *CHxO adsorption to facilitate electrocatalytic reduction of CO2 to CH4

Catalysts for the generation of methane in electrochemical CO2 reduction reactions (CO2RR) must have suitable adsorption energies for the intermediate products. In this study, we used a one-step electrodeposition method to prepare nitrogen(N) and phosphorus(P)-doped copper(Cu)-based catalysts. The introduction of P to the catalyst resulted in a significant change in the CO2RR pathway, leading to efficient and highly selective methane production. The Cu-N2-P2 electrocatalyst exhibits a CH4 Faradaic efficiency (FE) of 73 % at a potential of −1.6 V vs RHE, and it was found to be more effective in promoting the hydrogenation process of *CHO-*CH2O-*CH3O, which was confirmed by in-situ IR, X-ray absorption techniques and DFT calculations. P serves as the primary electron donation site in the catalyst, thereby influencing the charge distribution properties of the surrounding Cu atoms. This, in turn, facilitates the regulation of intermediate adsorption, representing the primary factor in the notable enhancement of methane selectivity.

Preparation of presulfided oil-soluble NiMo catalyst for slurry bed hydrocracking of vacuum residue

Here, a method is proposed for constructing presulfided oil-soluble NiMo catalysts using tetrathiomolybdate nickel ammonium as a precursor via a chelating ligand exchange strategy. Leveraging the close chemical bonding between Ni and Mo atoms, the NiMo catalyst can undergo in-situ self-sulfidation to generate active NiMoS sites and a composite structure of Ni3S2 and MoS2 nano phase in tight contact, thus exhibiting strong synergistic effects. The NiMo catalyst exhibited outstanding performance in hydrocracking of vacuum residue (VR) achieving a 64.7 wt% VR conversion while maintaining a coke yield of 0.51 wt%, as well as the excellent hydrogenation activity of polycyclic aromatic hydrocarbons. Combined with density functional theory calculations, it was further revealed that the presence of Ni reduces the energy barrier for H2 dissociation on MoS2, thereby enhancing the hydrogenation activity of the catalyst and its ability to suppress coke formation. This work validates the efficient bimetallic synergistic catalytic effect of presulfided oil-soluble NiMo catalysts in the slurry bed hydrocracking process.

Engineering Oxygen Vacancies of Co-Mn-Ni-Fe-Al High-Entropy Spinel Oxides by Adjusting Co Content for Enhanced Catalytic Combustion of Propane.

Transition metal-based oxides with similar oxidation activities for catalytic hydrocarbon combustion have attracted much attention. In this study, a new class of metal high-entropy oxides (CoxMnNiFeAl)3O4 (x = 1, 2, 3, 4, 5) with a porous structure was fabricated through a simple and inexpensive NaCl template-assisted sol-gel approach, which was employed for the catalytic oxidation of propane. The results indicated that the content of cobalt has a great impact on its activity, and the (Co4MnNiFeAl)3O4 catalyst exhibited the best catalytic activity. At the high space velocity of 60 000 mL·g-1·h-1, the optimized one with high-temperature treatment can still achieve 90% propane conversion at 309 °C, which is 68 and 178 °C lower than those of the (CoMnNiFeAl)3O4 catalyst and pure cobalt oxide, respectively. Meanwhile, it has the lowest apparent activation energy (46.6 KJ·mol-1) and the fastest reaction rate (26.976 × 10-6 mol·gcat-1·s-1 at 290 °C). The improved performance of the (Co4MnNiFeAl)3O4 catalyst could be attributed to the enhancement of low-temperature reducibility, the increased number of reactive surface oxygen species, and the cocktail effect of the high-entropy oxides. This work provides new insights into the preparation of efficient light alkane degradation catalysts and a realistic approach for the large-scale application of high-entropy oxides in the field of oxidation catalysts.

Uncovering the roles of Ce and Mn for NH3-SCR over Mn-Ce/IM-5 with extraordinarily superior wide-temperature performance

The development of wide-temperature catalyst with glorious activity and the resistance of SO2 for NH3-SCR reaction are of great importance. However, the preparation of wide-temperature catalyst with outstanding NH3-SCR performance and the resistance of SO2 is still challenging. In this work, Mn and Ce modified IM-5 molecular sieve catalyst (MC-5) was synthesized by incipient wetness impregnation method and the relationship of structure-activity was studied. MC-5 exhibited superior NOx conversion and it was more than 87% in the temperature range of 150-500 °C and ca. 100% at 225 °C due to the high concentration of Mn4+ and chemisorbed oxygen, the excellent redox ability and the synergistic effect of Mn and Ce. Meanwhile, the redox cycle of Mn4++Ce3+↔Mn3++Ce4+ promoted the electron transfer. 27Al NMR spectra and NH3-TPD confirmed Mn ion was mainly located on the bridge hydroxyl group (Brønsted acid sites). The localization energies ΔE of (Al, Mn) for IM-5 was determined by theoretical calculation and the reaction mechanism of M-5 catalyst on Brønsted acid sites was proposed. The reaction mechanism of M-5 catalyst on Brønsted acid sites followed L-H mechanism. And interestingly enough, the NH3-SCR activity of MC-5 significantly increased in the presence of SO2 at 200 °C. One of the reasons was that Ce binded more easily to SO42- and thus protected the active site Mn from sulfation. The other reason was the generation of more acid sites.

Preparation of Non-Noble Metal Catalyst FeCo2O4/MoS2 for Production of Hydrogen and Oxygen by Electrochemical Decomposition of Water

Preparation of Non-Noble Metal Catalyst FeCo2O4/MoS2 for Production of Hydrogen and Oxygen by Electrochemical Decomposition of Water

Peroxydisulfate activation by copper nanoparticles doped highly graphitized hollow carbon spheres for thiocyanate degradation

Thiocyanate (SCN-) is a toxic and refractory inorganic pollutant commonly found in industrial wastewater. This paper proposes an innovative solution to enhance the activation of peroxydisulfate (PDS) by designing a highly graphitized hollow carbon nanosphere structure catalyst doped with copper nanoparticles, thereby achieving efficient and complete degradation of SCN-. Specifically, the active sites and electron transfer ability of the catalyst were improved by controlling the pyrolysis temperature and acid etching time during the catalyst preparation process, thereby optimizing the PDS activation rate and SCN- degradation rate. In the optimized Cu-NPs@C/PDS system, a low dose of Cu-NPs@C-650–6 catalyst (0.2 g/L) and PDS ([PDS]0: [SCN-]0 = 3: 1) was sufficient to achieve 100 % degradation of 100 mg/L SCN- within 20 min. The non-radical oxidation pathway combined with singlet oxygen (1O2) and direct electron transfer process was identified as the main degradation mechanism of SCN-. The unique oxidation mechanism provided a higher SCN- degradation reaction rate constant (k1 = 0.39 min−1) and stronger environmental ion resistance. Density functional theory (DFT) calculations show that the CO bond is the primary PDS active site for the formation of inside-out electron delocalization, and the S atom in SCN- is a vulnerable site. This work offers technological support for the treatment of water bodies holding emerging electron-rich pollutants in addition to fresh insights into the creation of efficient catalysts for metal-carbon composites.

Synthesis of nitrogen-rich porous carbon via a molecular confinement strategy for activating peroxymonosulfate in bisphenol A degradation: Role of singlet oxygen and electron transfer process

Nitrogen-doped porous carbon (NPC) catalysts show potential for activating peroxymonosulfate (PMS) to treat water pollution. However, nitrogen (N) experiences significant loss during pyrolysis, posing challenges for synthesizing N-rich carbon catalysts. This study innovatively proposed a molecular confinement strategy using the C−S−C bond formed between graphitic carbon nitride and mercaptan. Under this confinement, we successfully synthesized NPC-15 with a high N content (21.4 at%), surpassing most catalysts reported in the literature. NPC-15/PMS system showed excellent performance in degrading bisphenol A (BPA), achieving complete degradation within 3 min (kobs = 1.771 min−1), surpassing the effectiveness of most previously reported catalysts. The NPC-15/PMS system exhibited excellent performance and stability under various conditions, reducing BPA toxicity to ecological and human embryonic kidney cells. Moreover, it maintained stability during long-term continuous operation in a fixed-bed reactor, showing promise for practical applications. Through experiments and theoretical calculations, the mechanism of NPC-15 activating PMS was comprehensively investigated. The NPC/PMS system operated via a dual non-radical pathway involving singlet oxygen and electron transfer process induced by pyridinic N and graphitic N dual active sites. Pyridinic N promoted the generation of 1O2, while graphitic N supported the electron transfer process. This study introduced a new strategy for the preparation of N-rich carbon catalysts and proposed a novel method for the removal of emerging pollutants in water.

Unlocking solid waste utilization: Fly ash-supported cobalt catalyzed transformation of 5-hydroxymethylfurfural into biofuel 2,5-dimethylfuran

5-Hydroxymethylfurfural is a crucial platform molecule derived from biomass, and its selective conversion to furan chemicals holds significant importance for the high-value utilization of biomass. In this study, acid-modified coal fly ash was used as a support for non-precious metal cobalt to prepare a novel catalyst (Co/CFA), which demonstrated excellent performance in the selective hydrodeoxygenation of 5-hydroxymethylfurfural to 2,5-dimethylfuran. By investigating the catalyst preparation conditions, it was found that with a 30wt% cobalt loading, the selectivity of 2,5-dimethylfuran can reach 98.1 %, and the conversion of 5-hydroxymethylfurfural is 99.0 %. A series of characterization showed that the acid modification treatment increased the pore structure and specific surface area of the coal fly ash, was conducive to the dispersion of cobalt, and improved the activity of the Co/CFA catalyst. This innovative approach harnesses the potential of waste materials, emphasizing resource efficiency and sustainability in catalyst development.

Structurally optimized rosette-like microspheres carbon with Fe-Ni single atom sites for bifunctional oxygen electrocatalysis in Zinc-Air batteries

Developing a secure and effective bifunctional oxygen catalyst for the ORR and OER is still a significant obstacle in the design of rechargeable zinc-air batteries. Here, a hollow rose-shaped bifunctional electrocatalyst is synthesized with an sacrificial template strategy (FeNi-NC). X-ray absorption fine structure analysis reveals the FeNi-NC catalyst contains FeN4 and NiN4 active sites as well as FeNi3 alloy. This hollow, flower-like structure performs low density, large specific surface area, and high permeability. Its inner cavities not only provide additional triple-phase interfaces to accelerate the reduction and oxidation of O2, but also enhance the diffusion of reactants on the catalyst. By controlling the input of Fe and nickel metal salts, the dispersion of active sites can be effectively tuned. Owing to the large number of exposed active sites on the carbon nanosheets, the synthesized FeNi-NC catalysts exhibit high electrocatalytic activity in both ORR (E1/2 = 0.852 V) and OER (ηj=10 = 359 mV). The construction of rechargeable zinc-air batteries resulted in a high power density of 135.78 mW cm−2, a better specific capacitance of 726.9 Wh kgZn−1 and 210 h enduring durability. More importantly, density functional theory (DFT) calculations indicate that the electronic interactions between Fe/Ni and nitrogen-doped carbon matrices play a pivotal role in enhancing the electrocatalytic performance of functional groups. These interactions effectively disrupt the electronic neutrality of carbon atoms, thereby accelerating the kinetics of the reaction. This research provides a new method for the preparation of single atom catalysts with bifunctional activities.

Facile synthesis of a novel CeCO3OH@(H/C–CdS) catalyst with synergistic effect of heterophase junction and heterojunction for enhanced visible-light photocatalytic degradation efficiency at room temperature

A new CeCO3OH@(hexagonal/cubic phases–CdS) (CeCO3OH@(H/C–CdS)) composite catalyst was facilely synthesized by a simple microinjection titration–stirring method, in which CdS nanoparticles were dispersed on the surface of CeCO3OH nanolines. The optimal conditions for the preparation of composite catalysts with high photocatalytic performance were determined by single-factor experiments and response surface experiments. Under these conditions, the degradation rate of 30 mL 2.000 g/L rhodamine B (Rh B) by CeCO3OH@(H/C-CdS) in a photocatalytic reaction for 1 h at 25 °C was up to 86.81 % and its degradation rate in a photocatalytic reaction for 150 min was up to 99.62 %. The degradation rate could be maintained above 80 % even after six times recycling. Especially, the photocatalytic degradation efficiency of 2.000 g/L Rh B on the composite catalyst under sunlight and at room temperature for 30 min reached 97.66 %. Meanwhile, the large size of CeCO3OH considerably alleviated the agglomeration of CdS, providing more adsorption and active sites for visible light-mediated degradation of Rh B. Importantly, the Z-scheme charge transfer realized by CdS and CeCO3OH enhanced the efficient separation of photogenerated electrons and holes, and successfully inhibited the recombination of photogenerated electrons with holes. At the same time, owing to the low energy band difference between the two phases of CdS, charge was transferred between the hexagonal and cubic phases, leaving more effective photogenerated charge to participate in the degradation of Rh B. The synergism of the heterophase junction and heterojunction and the presence of oxygen and sulfur vacancies considerably enhanced the degradation performance of the catalyst. Thus, this study provides a new strategy for the modification and enhanced visible-light catalysis performance of CdS-based catalysts.

Facile Synthesis of Ni(OH)2 through Low-Temperature N-Doping for Efficient Hydrogen Evolution

Nickel hydroxide is a potentially cheap non-precious metal catalytic material for alkaline hydrogen evolution reactions (HERs). Herein, a nickel form (NF)-based nitrogen-modified nickel hydroxide (N-Ni(OH)2/NF) with interlaced two-dimensional (2D) nanosheet structures was synthesized by a simple one-step ammonia vapor-phase hydrothermal method for efficient electrocatalytic HERs. The effect of the reaction temperature of the catalyst preparation on the HERs’ performance was studied in detail. The HER activity of N-Ni(OH)2/NF is enhanced by the large specific surface area, mass transfer and electron conductivity provided by a unique and suitable 2D nanostructure and nitrogen doping. The obtained N-Ni(OH)2/NF not only shows a superior HERs performance, but also exhibits good stability during long-term electrolysis.

An Efficient and Stable MXene-Immobilized, Cobalt-Based Catalyst for Hydrogen Evolution Reaction

Hydrogen (H2) is considered to be the best carbon-free energy carrier that can replace fossil fuels because of its high energy density and the advantages of not producing greenhouse gases and air pollutants. As a green and sustainable method for hydrogen production, the electrochemical hydrogen evolution reaction (HER) has received widespread attention. Currently, it is a great challenge to prepare economically stable electrocatalysts for the HER using non-precious metals. In this study, a Co/Co3O4/Ti3C2Tx catalyst was synthesized by supporting Co/Co3O4 with Ti3C2Tx. The results show that Co/Co3O4/Ti3C2Tx has excellent HER activity and durability in 1 mol L−1 KOH, and the overpotential and Tafel slope at 10 mA·cm−2 were 87 mV and 61.90 mV dec−1, respectively. The excellent HER activity and stability of Co/Co3O4/Ti3C2Tx can be explained as follows: Ti3C2Tx provides a stable skeleton and a large number of attachment sites for Co/Co3O4, thus exposing more active sites; the unique two-dimensional structure of Ti3C2Tx provides an efficient conductive network for rapid electron transfer between the electrolyte and the catalyst during electrocatalysis; Co3O4 makes the Co/Co3O4/Ti3C2Tx catalyst more hydrophilic, which can accelerate the release rate of bubbles; Co/Co3O4 can accelerate the adsorption and deionization of H2O to synthesize H2. This study provides a new approach for the design and preparation of low-cost and high-performance HER catalysts.

Anchoring nickel sites on ceria-coated silica to enhance the catalytic stability for the vapor phase levulinic acid hydrogenation

The preparation of the binary metal NiCe-based catalysts involved a 2-step protocol, the ceria was first coated on SiO2 which was then utilized to disperse Ni nanoparticles. Various techniques including N2 adsorption/desorption, ICP-OES, XRD, HRTEM, XPS, H2-chemisorption, H2-TPR, NH3-TPD, and TG etc. were performed to study the microstructure, redox, acid property and deactivation. The results revealed that CeO2 and metallic Ni were well dispersed on the support surface, the synergistic effect between the two metal species was conserved well. The content of CeO2 had considerable effects on redox and metallic properties rather than the acidic property. The dispersion of metallic Ni played a dominant role in promoting the catalytic activity. The levulinic acid conversion attained 84.0 % with a γ-valerolactone selectivity of 98.8 % on Ni/SiO2@2CeO2 sample with the highest dispersion of 9.8 %. The amorphous CeO2 suppressed the sintering of metallic Ni nanoparticles and improved the coke resistance, leading to better catalytic activity within 20 h time on stream.