Supported Ni Catalysts Research Articles

Role of Active Site and CO2-Interacting Surface Species in Dry Reforming of Methane over Strontium Promoted Ni Catalyst Supported by Lanthanum-Zirconia.

In the context of global warming, the dry reforming of methane (DRM) has gained significant attention due to its ability to simultaneously deplete two greenhouse gases, i. e. CH4 and CO2, and generate syngas. Herein, strontium-promoted Lanthanum-zirconia supported Ni catalysts are investigated for DRM and characterized by X-ray diffraction, surface area and porosity, FTIR-RAMAN spectroscopy, and temperature-programmed experiments. The Ni/LaZr catalyst contains formate and oxycarbonate-like CO2-interacting species, while strontium-promoted catalysts have additional ionic CO3 2- species. The current catalyst system of 2 % strontium-promoted Ni/LaZr has active sites derived from three types of NiO: easily reducible, moderately interacted, and strongly interacted. During the DRM reaction over the current system, CO2 is a better oxidant than O2 for removing carbon deposits. Additionally, the catalysts attain higher reducibility under oxidizing gas (CO2) and reducing gas (H2) during the DRM reaction. For optimal hydrogen yield of approximately 60 % within 420 minutes of operation over Ni2Sr/LaZr catalyst, a balance between the population of active site Ni and CO2-interacting surface species is necessary.

MCM-41 from rice husk silica as a support for Ni catalyst in the emission-free production of H2 by CH4 cracking.

Selecting a sustainable source of silica from biomass waste was the research challenge that was put forth in this investigation. Herein, the MCM-41 support has been synthesized using a renewable rice husk and explored as a support for Ni-Cu catalyst in the production of zero-emission H2 through CH4 pyrolysis. The role of Cu promoter was investigated by doping different amounts of Cu loading to 30wt%Ni/R-MCM-41catalyst, which improved the catalytic performance in terms of CH4 conversion and stability. An optimum Cu loading of 3wt% addition to 30wt%Ni/R-MCM-41 catalyst demonstrated the best catalytic performance compared to all the catalysts in terms of hydrogen yield (15,218mol H2/mol Ni) and carbon formation rate. The Ni-Cu alloy formation was confirmed by X-ray diffraction, H2-temperature programmed reduction, and pulse chemisorption studies, as demonstrated by decreased H2 uptake (from 41 to 33μmol/gcat) and enhanced N2O (from 89.2 to 138.3μmol/g) uptakes, which results in a significant improvement in the availability of the surface metal species (both Cu and Ni), which in turn contributed to increase the CH4 cracking performance and stabilization of Ni species. Additionally, doping Cu results in better carbon nanotube production, as shown by the lowest ID/IG ratio from the Raman spectroscopic analysis.

A comprehensive characterisation of food waste for its sustainable and holistic management using thermochemical processes

ABSTRACT This work presents a comprehensive physico-chemical analysis of mixed food waste (MFW) as a good feed for the thermochemical conversion process followed by its utilisation in the pyrolysis and gasification processes. The chemical analysis showed that MFW contained not only typical biomass contents, such as lignin (15.04%), cellulose (26.20%) and hemicellulose (5.05%) but also nutrients, such as protein (12.15%), starch (14.13%) and lipids (25.02%). Additionally, physical analyses, such as TGA, XRD, FTIR and FESEM, shed light on thermal behaviour, morphological structural and functional substituents in food waste. Post-analysis, 100-gm food waste was processed first via pyrolysis to produce bio-oil (40%) and bio-char (27%), then the biochar generated from pyrolysis was used as a feed in the steam gasification process which produced syngas (2.75 m3/Kg) as a main product and food waste ash as a side product. This food waste ash, in turn, was used as a support and promoter for Ni catalyst whose use in steam gasification showed a substantial increase in syngas production (1.26 m3/Kg from RFW and 3.6 m3/kg from bio-char).

Investigation of a novel Defatted Spent Coffee Ground (DSCG)-supported Ni catalyst for fuel cell and supercapacitor applications

With the increase in energy demand, a material that can be used in fuel cell applications has been developed for both energy storage and the use of alternative energy sources to fossil fuels. In this study, a new Defatted Spent Coffee Ground (DSCG)-based electrode material was synthesized for two different application areas. A new electrocatalyst synthesis was carried out by subjecting DSCG to chemical activation and carbonization processes. The glycerol electrooxidation performances of the catalysts synthesized at 10–50 % Ni loading rates were investigated by CV measurements. 30 % Ni-DSCG catalyst exhibited the highest catalytic activity with 3.290 mA/cm2.As a result of the electrochemical measurements, 30 % Ni-DSCG catalyst with the best catalytic performance was used as the supercapacitor electrode material. The electrochemical performances of the produced supercapacitor electrodes were tested at room temperature using galvanostatic charge-discharge (GCD), Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques, and the capacity and stability of the electrodes were calculated as a result of the findings. In the calculations, the energy and power density of the 30 % Ni-DSCG supercapacitor electrode were calculated as 22.897 Wh kg−1, 841.114 W kg−1, respectively. The supercapacitor electrode capacitance was found to be 50.48 F/g.Its cyclic capacity was found to be 90 %. It showed that the DSCG-based synthesized electrocatalyst could be a good option for energy storage technology as EDLC electrode material and fuel cell applications as anode catalyst due to its good conductivity, superior cyclic stability, environmental friendliness and low cost.

Design and Synthesis of a Novel Catalytic System Based on Pd Supported on Alumina Extrudates for Hydrotreating of PAO Lubricants

ABSTRACTThe development of hydrogenation processes for polyalphaolefin (PAO) lubricants, which hold commercialization potential, is a challenging endeavor. Here, we synthesized and characterized rod‐shaped γ‐alumina supported Pd catalyst for PAO hydrofinishing, comparing it with γ‐alumina supported Ni catalyst. Results indicated that Pd/Al2O3 catalyst efficiently promoted PAO hydrofinishing, whereas Ni‐based catalyst exhibited lower activity. Optimization of reaction variables using the one‐factor‐at‐a‐time method revealed that hydrogenated polyalphaolefin could be achieved with a 90% yield using a 5 wt.% catalyst, a hydrogen pressure of 12 bar, at 130°C after 7 h. The superior performance of the fabricated catalysts, coupled with the use of rod‐shaped alumina suitable for large‐scale hydrogenation reactors, suggests the versatility of the process for potential commercialization. Additionally, the higher performance of Pd/alumina compared to Ni/alumina catalyst was computationally assessed at the molecular level using DFT methods.

CATALYTIC PROCESSING OF COAL MINE METHANE INTO HYDROGEN-CONTAINING GAS: INFLUENCE OF TRI-REFORMING PROCESS CONDITIONS

In order to develop a catalytic technology for processing coal mine methane into hydrogen-containing gas, thermodynamic analysis of methane tri-reforming (TRM) was carried out, and the influence of temperature (600-850 °C), contact time (0.04-0.15 s), linear feed rate (80-240 cm/min) and composition (CH4 / CO2 / H2O / O2 / He = 1: (0.3-0.5) : (0.2-0.5) : (0.1-0.3) : (2.9-3.2)) of the reaction mixture on the conversion of the initial reagents and target products in the TRM process in the presence of a supported Ni catalyst was studied. It has been shown that with an increase in the temperature of the TRM reaction from 600 to 800 °C the process performance improves (methane conversion: 36 → 94 %, carbon dioxide conversion: 57 → 97 %, hydrogen yield: 37→91 %, carbon monoxide yield: 44→ 94 %, molar ratio H2/CO: 1.5 → 1.7), and at a reaction temperature of 850 °C the process indicators are close to equilibrium values. It has been established that varying the O/C value and the composition of oxidants makes it possible to regulate the performance of TRM process. The optimal conditions for the TRM process were identified to achieve maximum efficiency of the catalytic processing of coal mine methane into hydrogen-containing gas: temperature - in the range of 800-850 °C, contact time - 0.15 s, linear feed rate - 160 cm/min and molar ratio of reagents in the initial feed - CH4 / CO2 / H2O / O2 = 1: 0.5 : 0.2 : 0.25.

CO2 methanation under more realistic conditions: Influence of O2 and H2O on Ni-based catalysts’ performance

In this work, Ni-based catalysts (15 wt%) promoted with Y (15 wt%) and Fe (1 wt%) supported on an optimized USY zeolite were prepared by incipient wetness co-impregnation, characterized by XRD, TGA, N2 adsorption, H2-TPR, and TEM, and finally tested towards CO2 methanation (total flow of 274 mL/min, H2/CO2 = 4, 2.5 bar and 0.2 g of catalyst) including water or oxygen in the feed. On one side, water (∼5 vol%) shows a limited impact on catalysts’ performance despite being a product of the CO2 methanation reaction. These results were mainly attributed to the high hydrophobicity of the studied catalysts, as well as to the absence of additional/competitive reactions. On the other side, oxygen (∼4 vol%) negatively affected the activity of the tested catalysts, decreasing the CO2 conversion, particularly for the unpromoted catalysts. Two different aspects were found to be responsible for the decline in activity: on the one hand, the H2/O2 reaction, which is faster than the CO2 methanation and decreases H2 availability for Sabatier reaction; on the other hand, the partial re-oxidation of nickel active sites, evidenced by post-test characterization, which decreases the number of Ni0 active sites, and therefore, leads to a drop in CO2 conversion. Reversibility tests to assess O2 effect were also performed, indicating that its impact on the catalytic performances mainly arises from the decrease in H2 partial pressure, leading to operation under sub-stoichiometric CO2 methanation conditions (H2/CO2 ∼ 3). When compared to a commercial Al2O3–supported Ni catalyst, zeolite-based samples demonstrated superior resistance to H2O and O2.

Effect of the reorganization of acid sites induced by metal species on TiO2 supports on the conversion of furfural to acetals and ethers

For the catalytic hydrogenation of furfural (FFR) over supported metal catalysts, acetals and ethers were often observed as by-products when alcohols were used as solvents. The presence of specific acid sites on the catalyst led to the conversion of FFR to acetals and ethers. To understand the effect of the interaction between metal species and oxide supports on the acid properties of catalysts and the conversion of FFR to acetals and ethers, anatase TiO2 (TiO2-A), rutile TiO2 (TiO2-R) and these TiO2 supported Ni catalysts were studied as models. The relationship between the acid properties of these samples and FFR conversion pathways in isopropanol was revealed. The interaction between Ni species and TiO2 supports was found to selectively remove Brønsted acid sites on the TiO2 supports in the absence of H2, thereby inhibiting the conversion of FFR to acetals and ethers in N2. However, the presence of high-pressure H2 during the reaction induced the formation of new Brønsted acid sites on Ni/TiO2 catalysts via hydrogen spillover, promoting the acetalization of FFR to acetals and the hydrogenolysis of acetals to ethers. The Ni/TiO2-A catalyst exhibited higher activity in catalyzing the conversion of FFR to acetals and ethers compared to the Ni/TiO2-R catalyst. This work provides reference information for the selective regulation of acid-catalyzed reaction pathways of FFR in alcohols.

Reaction synergy of bimetallic catalysts on ZSM-5 support in tailoring plastic pyrolysis for hydrogen and value-added product production

Hydrogen, viz. a green energy carrier, is poised to considerably contribute to the empowerment of a sustainable society. By valorizing plastics, catalytic pyrolysis was envisaged as a promising route to produce green hydrogen and value-added product here. Firstly, the screening of optimal catalyst support (from activated carbon and four zeolites: M-zeolite, B-zeolite, Y-zeolite, ZSM-5) was executed by studying catalytic polypropylene (PP) pyrolysis over supported Ni catalysts. In view of the highest H2 yield (19.2 mmol/gPP) of Ni/ZSM-5, ZSM-5 was put forth as the optimal catalyst support. Then, the identification of optimal active metal (from Ni, Fe, Co, FeNi, FeCo, and NiCo) was performed by running the catalytic PP pyrolysis over ZSM-5 supported catalysts. For catalytic PP pyrolysis, NiCo/ZSM-5 was the optimal catalyst with the highest H2 yield (28.7 mmol/gPP), while the resulting pyrolysis oil demonstrated potential for use as jet fuel. From catalytic pyrolysis of various plastics over NiCo/ZSM-5, polystyrene gave the highest H2 composition (83.2 vol%) of pyrolysis gas and high composition (52.8 area%) of benzocyclobutene (useful chemicals for semiconductor and microelectronics fields) in pyrolysis oil. Lastly, the catalytic mechanism was discussed based on the results, revealing NiCo's remarkable enhancement in H2 yield to 28.7 mmol/g, which surpassed the individual yields of Ni (19.2 mmol/g) and Co (10.2 mmol/g), thereby underscoring the synergistic effect of NiCo. This study supports the recycling of plastics waste into hydrogen energy and valuable products, contributing to environmental pollution mitigation.

Production of bio-crude from co-pyrolysis of oil shale and peanut shell over semi-coke supported Ni catalyst

Bio-crude producted from the co-pyrolysis of oil shale and peanut shell over a Ni-based catalyst supported on semi-coke was investigated in a vertical double-temperature zone fixed bed reactor. The effect of Ni species loading on the characteristics of bio-crude was evaluated. Results indicated that the effective H/C and calorific value of bio-crude gradually increased and the average carbon chain length gradually decreased with the increase of Ni species loading. The average carbon chain length decreased from 17.54 to 12.61 when the Ni loading was 9 %. An analysis of liquid product components indicated that the presence of the catalyst promoted the combination of small molecular side chains generated by oil shale fractures and active molecules generated by peanut shell thermal decomposition, increasing the generation of phenolic compounds. Furthermore, the phenolic compounds were further converted to aromatic hydrocarbons by promoting the alkylation transfer of the methoxy group to the benzene ring, demethoxylation, and dehydration reactions.

Oxygen Vacancies Enrichment in Citric Acid-Assisted Synthesis of Zirconia Supported Ni Catalyst for Highly Selective Hydrogenolysis of 5-Hydroxymethylfurfural.

2, 5-Dimethylfuran (DMF), which is a promising new-generation liquid biofuel, has attracted widespread attention owing to the sustainability of biomass-derived energy sources. In this study, a highly dispersed zirconia-supported nickel catalyst (CA-Ni/ZrO2) was prepared via citric acid-assisted wetness impregnation for the selective hydrogenolysis of 5-hydroxymethylfurfural (HMF) to produce DMF. The characterization results confirmed the presence of Zr3+ species in the mesoporous CA-Ni/ZrO2 catalyst and the formation of oxygen vacancies during its preparation, which led to the formation of a large number of catalytically active sites for the adsorption and activation of the C=O/C-O groups. Under appropriate reaction parameters, an excellent DMF selectivity of 99.1 % and an HMF conversion of 98.4 % were achieved. A suitable kinetic model revealed that DMF was preferentially formed via the 2,5-dihydroxymethylfuran intermediate route, although a 5-methylfurfural route was also observed. Additionally, the interaction between Ni and ZrO2 significantly affected the stability of the catalyst. This study will provide guidelines for optimizing the catalytic conversion of furan derivatives over heterogeneous catalysts.

Core‐Shell Zeolite with Confined Nickel Particles as Prominent Catalyst for the Hydrogenation of Maleic Anhydride

AbstractTransformation of maleic anhydride (MA) into succinic anhydride (SA) through the development of high‐performance catalysts is an appealing approach from a sustainable development perspective. Herein, a core‐shell catalyst with silicate‐1 supported and MCM‐41 encapsulated nickel was prepared, which exhibited extraordinarily high MA conversion (99.8 %) and SA selectivity (99.9 %). Detailed structural characterizations and catalytic evaluation demonstrated that the core‐shell catalyst derived from the liquid deposition method is a hierarchically porous material with tunable shell thicknesses, possessing strong interaction between Ni particles and the supports. Key to this success is the MCM‐41 shell that covered the defects such as silanol nests on the surface of the silicate‐1 zeolite, diminishing both the surface and intra‐particle diffusion barriers, thus the specially‐designed catalyst achieved high activity under rather mild conditions (100 °C, 3.0 MPa), which is 59 % higher than the conventional silicate‐1 supported Ni catalyst. Furthermore, the mesoporous MCM‐41 shell plays a crucial role in minimizing the leaching and sintering of Ni particles, thereby bolstering catalytic stability. Overall, the research provides a new approach for the rational design to optimize the performance of hydrogenation catalysts and introduces a novel idea to enhance the activity and stability of Ni‐supported catalysts.

The promoting role of framework Ti(IV) in enhancing the hydrodeoxygenation performance of palmitic acid over a mesoporous TS-1 supported Ni catalyst

Developing a highly efficient Ni-based hydrodeoxygenation catalyst is crucial for the production of renewable biodiesel. Herein, a mesoporous TS-1 zeolite supported Ni catalyst (Ni/TS-1-M) exhibited exceptional hydrodeoxygenation (HDO) activity and achieved 100 % yield of deoxygenated hydrocarbons (97.3 % pentadecane vs 2.7 % hexadecane), outperforming other catalysts such as Ni on mesoporous ZSM-5 (Ni/ZSM-5-M), mesoporous Silicalite-1 (Ni/Silicalite-1-M) and TiO2 (Ni/TiO2). The Ti(IV) atoms in the form of TiO4 and TiO6 can transfer its electron to nearby metal Ni, leading to the increase in electron density of metal Ni, which enhanced the hydrogenation activity and facilitated the C–C bond cleavage of the hexadecanal to produce pentadecane. Furthermore, the framework Ti(IV) species accelerated the esterification process to generate palmityl palmitate, which was easily hydrogenolyzed to the main intermediate of hexadecanol under the synergistic effect of metal Ni and Ti(IV) on Ni/TS-1-M catalyst. The formed hexadecanol mainly underwent successive dehydrogenation/decarbonylation process to transform into pentadecane.

Structure and oxygen evolution reaction performance of Ni-supported catalysts based on steam-exploded poplar

Using renewable steam-exploded poplar (SEP) as carbon source, nickel metal doped carbon hybrid materials were designed to synthesize catalysts (Ni/SEP) with certain oxygen evolution reaction (OER) properties and were compared with nickel catalysts supported on metal organic framework structure (ZIF67-Ni). The roles of SEP support in Ni-based catalyst were considered. Scanning electron microscope (SEM) images confirmed that the fiber could better hinder the aggregation of metal particles. Fourier transform infrared spectroscopy (FT-IR) indicated the presence of surface OH groups after the reduction process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses confirmed the major form of metallic Ni in the resulting Ni catalysts. Carbon materials as carriers, the synergetic effect of Ni-doped, and carbon carrier played an important role in facilitating the kinetics of OER, which was similar to the carrier of metal-organic frame material. Notably, the Ni/SEP (11.3 mF/cm-2) and ZIF67-Ni (37.2 mF/cm-2) with better OER performance exhibited a smaller double layer capacitances (Cdl), suggesting the intrinsic OER catalytic activity of the Ni/SEP and ZIF67-Ni were much higher in comparison to the ZIF67-Ni/SEP. Moreover, the inferior performance of Ni/SEP further indicated that the synergistic effect between carbon and Ni/NiO contributes to the enhanced OER activity.

Enhanced hydrogen production through methane dry reforming: Evaluating the effects of promoter-induced variations in reducibility, basicity, and crystallinity on Ni/ZSM-5 catalyst performance

The pursuit of sustainable hydrogen production through the conversion of methane (CH4) and carbon dioxide (CO2), two prevalent greenhouse gases, is advanced by utilizing cost-effective Ni-supported catalysts within the framework of methane dry reforming. Utilizing crystalline porous zeolite, specifically ZSM-5, enhances the dispersion of nickel (Ni) across the catalyst surface and within its pore channels, hence increasing catalytic efficiency. Herein, we investigate the impact of incorporating various promoters (Ce, Cs, Cu, Fe, Sr) into the 5Ni/ZSM-5 catalyst, systematically examining how these modifications influence the reducibility, basicity, and crystallinity of the catalyst’s active sites, thereby affecting its hydrogen yield potential.Our findings reveal that the inferior activity of Cu-promoted catalysts is due to the depletion of basic sites and larger NiO crystallite size (than rest-promoted catalysts). The introduction of Fe results in a highly dispersed Ni with a stable NiFe phase, but dilution of active sites results in low hydrogen yield. Conversely, Sr promotion enhances the basicity and accessibility of NiO active sites both on the surface and within the pore channels of the zeolite, leading to a notable hydrogen yield of 28 % at 700℃ after 300 min. Furthermore, the addition of 2 wt% ceria significantly optimizes Ni dispersion within the pore channels and surges the maximum population of basic sites (including the presence of very strong basic sites), achieving 35 % hydrogen yield at 700 °C and ∼ 70 % at 800℃. This investigation underscores the critical role of promoter-induced modifications in enhancing catalyst performance for hydrogen production, contributing to the development of more efficient and sustainable energy conversion technologies.

Efficient reverse water gas shift reaction at low temperatures over an iron supported catalyst under an electric field

The development of high-performance Fe-based catalysts is attractive because Fe is a cost-effective and earth-abundant element. Application of an external electric field and an appropriate catalytic support to an Fe-based catalyst enabled the reverse water–gas shift reaction to proceed with high activity, selectivity, and durability even at the low temperature of 423 K. The Fe-supported catalyst showed superior CO selectivity (≈ 100%) compared to the Co- or Ni-supported catalyst. The apparent activation energy (5.9 kJ mol−1) over the Fe/Ce0.4Al0.1Zr0.5O2 catalyst under an electric field was much lower than that without an electric field (61.4 kJ mol−1).

Controlled dispersion of Ni catalyst on N-doped carbon support for stable and selective hydrogen production from formic acid

Formic acid is a liquid organic hydrogen carrier from which hydrogen can be released together with CO2 by catalytic decomposition. The development of supported Ni catalysts for H2 production is important. Here, the effects of Ni state/dispersion are considered. For this purpose, three samples were prepared with about 3 wt% Ni deposited on porous N-doped carbon. The first sample contained predominantly Ni nanoparticles (∼2 nm), the second contained Ni clusters (<1 nm), and the third – single-atom Ni sites. The catalysts showed close activity in the gas-phase reaction. However, a minimum apparent activation energy of 105 kJ/mol and a maximum selectivity towards H2 production of 99% were achieved for the single-atom Ni catalyst. The nature of its single-atom sites was established to correspond to Ni-N4 and Ni-O4, which showed greater stability under the conditions of the catalytic reaction.

Silica-supported Active Ni Nanocatalyst for Wittig Reaction

Abstract: The preparation and characterization of SBA-15 supported Ni catalysts with varying metal loading (1, 2, and 3% by weight) was carried out using the impregnation technique, followed by a rigorous characterization using advanced analytical techniques. The catalytic performance of the synthesized catalysts was evaluated for the Wittig-type olefination reaction, and it was found that the SBA- 15-3Ni catalyst exhibited superior activity for this reaction under mild reaction conditions (70°C and 1 hour). The corresponding stilbenes were obtained in good yield, although with low to average diastereoselectivity. An important feature of this protocol is that the proposed methodology is especially efficient for the synthesis of stilbenes since no additives are required to serve as a hydrogen acceptor. Moreover, the new catalytic system was successfully employed for the synthesis of polymethoxylated and polyhydroxylated stilbenes, including resveratrol and DMU-212, with high yield and easy product isolation. A key advantage of this protocol is that the catalysts can be reused for up to 5 runs without significant loss in catalytic activity, which makes this approach highly sustainable and cost-effective. Additionally, the ligand-free approach proposed in this study is an added advantage, which makes it more attractive for large-scale synthesis of biologically active compounds.

Jet fuel production via palm oil hydrodeoxygenation over bifunctional zeolite mixture supported Ni catalyst: Effect of Si/Al ratio

The influence of the Si/Al ratio of ZSM-5 on 10 wt% Ni/ZSM-5.SAPO-11 catalysts were investigated through the palm oil hydrodeoxygenation (HDO) process, based on the product selectivity of alternative jet fuel. This study utilizes a 1 L batch reactor at 60 bar and 350 °C for palm oil hydrodeoxygenation over 10 wt% Ni/ZSM-5.SAPO-11 catalysts. Si/Al ratio of 50 produces a 10 wt% Ni/ZSM-5.SAPO-11 catalyst with the optimum physicochemical properties for palm oil hydrodeoxygenation. TGA/DTG analysis of the spent catalyst shows that the catalyst has good thermal and catalyst stability with minor carbon deposition. GC/MS analysis also demonstrated a 100 % palm oil conversion to alternative jet fuel. The highest jet fuel yield of 51 % was attained with a Si/Al ratio of 50. The physicochemical properties of alternative jet fuel samples were measured to ensure that the conventional fuel standard limits were appropriately followed. These results indicated that such types of bifunctional Ni-based catalysts have the potential to be used in the conversion of triglycerides to alternative jet fuel.

Ammonia decomposition over vanadium oxide supported Ni catalyst for hydrogen production

The performance of vanadium oxides as support is investigated to develop a new nickel catalyst for ammonia decomposition to produce hydrogen. The catalytic activity is in the order of Ni/V2O3 > Ni/VO2 > Ni/V2O5, depending on the oxidation states of vanadium oxide. The VOx supports in all of the spent catalysts are V2O3, suggesting that V2O3 is the stable phase of VOx support during the ammonia decomposition. 3 wt%Ni/V2O3 gives an ammonia conversion of 38.3% (SV = 3000 L kg−1h−1) at 530 °C. Excellent active sites with a TOF of 33.6 s−1 at 500 °C form on 3 wt%Ni/V2O3. Ni/VOx works effectively as a catalyst for ammonia decomposition to produce hydrogen.