Hydrogen production by steam reforming of ethanol over mesoporous Ni–Al2O3–ZrO2 aerogel catalyst

A mesoporous Ni–Al₂O₃–ZrO₂ aerogel (Ni–AZ) catalyst was prepared by a single-step epoxide-driven sol–gel method and a subsequent supercritical CO₂ drying method. For comparison, a mesoporous Al₂O₃–ZrO₂ aerogel (AZ) support was prepared by a single-step epoxide-driven sol–gel method, and subsequently, a mesoporous Ni/Al₂O₃–ZrO₂ aerogel (Ni/AZ) catalyst was prepared by an incipient wetness impregnation method. The effect of preparation method on the physicochemical properties and catalytic activities of Ni–AZ and Ni/AZ catalysts was investigated. Although both catalysts retained a mesoporous structure, Ni/AZ catalyst showed lower surface area than Ni–AZ catalyst. From TPR, XRD, and H₂–TPD results, it was revealed that Ni–AZ catalyst retained higher reducibility and higher nickel dispersion than Ni/AZ catalyst. In the hydrogen production by steam reforming of ethanol, both catalysts showed a stable catalytic performance with complete conversion of ethanol. However, Ni–AZ catalyst showed higher hydrogen yield than Ni/AZ catalyst. Superior textural properties, high reducibility, and high nickel surface area of Ni–AZ catalyst were responsible for its enhanced catalytic performance in the steam reforming of ethanol.     

Hydrogen production by steam reforming of ethanol over mesoporous Ni–Al2O3–ZrO2 xerogel catalysts: Effect of nickel content

Hydrogen production by steam reforming of ethanol over mesoporous Ni–Al₂O₃–ZrO₂ xerogel catalysts (denoted as XNiAZ) with different nickel content (X, wt%) was studied. A single-step epoxide-driven sol–gel method was employed for the preparation of the catalysts. The effect of nickel content of XNiAZ catalysts on their physicochemical properties and catalytic activities was investigated. All the XNiAZ catalysts exhibited a well-developed mesoporous structure and they dominantly showed an amorphous NiO–Al₂O₃–ZrO₂ composite phase, leading to high dispersion of NiO. Nickel surface area and reducibility of XNiAZ catalysts showed volcano-shaped trends with respect to nickel content. Nickel surface area of XNiAZ catalysts played a key role in determining the catalytic performance in the steam reforming of ethanol; an optimal nickel content was required for maximum production of hydrogen. Among the catalysts tested, 15NiAZ catalyst with the highest nickel surface area exhibited the best catalytic performance in the steam reforming of ethanol. In addition, 15NiAZ catalyst showed high and stable hydrogen yields under different total feed rate, demonstrating its potential applicability in large-scale hydrogen production.     

Hydrogen production by auto-thermal reforming of ethanol over nickel catalyst supported on metal oxide-stabilized zirconia

Metal oxide-stabilized mesoporous zirconia supports (M–ZrO₂) with different metal oxide stabilizer (M = Zr, Y, La, Ca, and Mg) were prepared by a templating sol–gel method. 20 wt% Ni catalysts supported on M–ZrO₂ (M = Zr, Y, La, Ca, and Mg) were then prepared by an incipient wetness impregnation method for use in hydrogen production by auto-thermal reforming of ethanol. The effect of metal oxide stabilizer (M = Zr, Y, La, Ca, and Mg) on the catalytic performance of supported nickel catalysts was investigated. Ni/M–ZrO₂ (M = Y, La, Ca, and Mg) catalysts exhibited a higher catalytic performance than Ni/Zr–ZrO₂, because surface oxygen vacancy of M–ZrO₂ (M = Y, La, Ca, and Mg) and reducibility of Ni/M–ZrO₂ (M = Y, La, Ca, and Mg) were enhanced by the addition of lower valent metal cation. Hydrogen yield over Ni/M–ZrO₂ (M = Zr, Y, La, Ca, and Mg) catalyst was monotonically increased with increasing both surface oxygen vacancy of M–ZrO₂ support and reducibility of Ni/M–ZrO₂ catalyst. Among the catalysts tested, Ni catalyst supported on yttria-stabilized mesoporous zirconia (Ni/Y–ZrO₂) showed the best catalytic performance.     

Comparative study on the promotion effect of Mn and Zr on the stability of Ni/SiO2 catalyst for CO2 reforming of methane

The stability of Mn-promoted Ni/SiO₂ catalyst for methane CO₂ reforming was investigated comparatively to that of Zr-promoted Ni/SiO₂. The catalysts were prepared by the same impregnation method with the same controlled promoter contents and characterized by TPR, XRD, TG, SEM, XPS and Raman techniques. The addition of Mn to Ni/SiO₂ catalyst promoted the dispersion of Ni species, leading to smaller particle size of NiO on the fresh Ni–Mn/SiO₂ catalyst and the formation of NiMn₂O₄, which enhanced the interaction of the modified support with Ni species. Thus, the Ni–Mn/SiO₂ catalyst showed higher activity and better ability of restraining carbon deposition than Ni/SiO₂ catalyst. Besides, it exhibited stable activity at reaction temperatures over the range from 600 °C to 800 °C. However, the introduction of Zr increased the reducibility of Ni–Zr/SiO₂, and the catalyst deactivated much more dramatically when the reaction temperature decreased due to its poor ability of restraining carbon deposition, and its activity decreased monotonically with time on stream at 800 °C.     

H2 production from oxidative steam reforming of 1-propanol and propylene glycol over yttria-stabilized supported bimetallic Ni–M (M = Pt,Ru, Ir) catalysts

This paper reports hydrogen production from oxidative steam reforming of 1-propanol and propylene glycol over Ni–M/Y₂O₃–ZrO₂ (10% wt/wt Y₂O₃; M = Ir, Pt, Ru) bimetallic catalysts promoted with K. The results are compared with those obtained over the corresponding monometallic catalyst. The catalytic performance of the calcined catalysts was analyzed in the temperature range 723–773 K, adjusting the total composition of the reactants to O/C = 4 and S/C = 3.2–3.1 (molar ratios). The bimetallic catalysts showed higher hydrogen selectivity and lower selectivity of byproducts than the monometallic catalyst, especially at 723 K. Ni–Ir performed best in the oxidative steam reforming of both 1-propanol and propylene glycol. The presence of the noble metal favours the reduction of the NiO and the partial reduction of the support. The NiO crystalline phase present in the calcined catalysts was transformed to Ni° during oxidative steam reforming. The adsorption and subsequent reactivity of both 1-propanol and propylene glycol over Ni–Ir and Ni catalysts were followed by FTIR; C–C bond cleavage was found to occur at a lower temperature in propylene glycol than in 1-propanol.     

Hydrogen production by steam reforming of ethanol over P123-assisted mesoporous Ni–Al2O3–ZrO2 xerogel catalysts

A series of mesoporous Ni–Al₂O₃–ZrO₂ xerogel (denoted as X-NAZ) catalysts were prepared by a P123-assisted epoxide-driven sol–gel method under different P123 concentration (X, mM), and they were applied to the hydrogen production by steam reforming of ethanol. The effect of P123 concentration on the physicochemical properties and catalytic activities of X-NAZ catalysts was investigated. All the catalysts retained a mesoporous structure. Pore volume of the catalysts increased with increasing P123 concentration. Ni surface area and ethanol adsorption capacity of X-NAZ catalysts exhibited volcano-shaped trends with respect to P123 concentration. The trend of hydrogen yield was well matched with the trend of Ni surface area and ethanol adsorption capacity. Thus, Ni surface area and ethanol adsorption capacity of the catalysts served as important factors determining the catalytic performance. Among the catalysts tested, 12-NAZ catalyst with the highest Ni surface area and the largest ethanol adsorption capacity showed the best catalytic performance in the steam reforming of ethanol. In conclusion, an optimal P123 concentration was required for maximum production of hydrogen in the steam reforming of ethanol over X-NAZ catalysts.     

Hydrogen production through methanol steam reforming: Effect of synthesis parameters on Ni–Cu/CaO–SiO2 catalysts activity

The objectives of this study were to prepare Ni–Cu/CaO–SiO₂ catalysts by a modified polyol process with different preparation conditions and evaluate the feasibility of hydrogen production from methanol steam reforming. CaO–SiO₂ materials possess high specific surface areas and CO₂ absorption capacities which were synthesized through the sol–gel method to serve as supports. The experimental results of the methanol steam reforming indicated that the highest catalytic activity was achieved when the Ni–Cu/CaO–SiO₂ catalyst was prepared under Ar atmosphere at a reduction temperature of 160 °C (160-Ar). The 160-Ar catalyst synthesized by this method has a large pore volume and a high mesoporosity. These physical properties contribute to the effective dispersion of metal particles in the 160-Ar catalyst. Increasing the MeOH/H₂O ratio was found to promote the water–gas shift reaction and direct methanol decomposition to produce more H₂.     

Syngas production by CO2 reforming of coke oven gas over Ni/La2O3–ZrO2 catalysts

Syngas production by CO₂ reforming of coke oven gas (COG) was studied in a fixed-bed reactor over Ni/La₂O₃–ZrO₂ catalysts. The catalysts were prepared by sol–gel technique and tested by XRF, BET, XRD, H₂-TPR, TEM and TG–DSC. The influence of nickel loadings and calcination temperature of the catalysts on reforming reaction was measured. The characterization results revealed that all of the catalysts present excellent resistance to coking. The catalyst with appropriate nickel content and calcination temperature has better dispersion of active metal and higher conversion. It is found that the Ni/La₂O₃–ZrO₂ catalyst with 10 wt% nickel loading provides the best catalytic activity with the conversions of CH₄ and CO₂ both more than 95% at 800 °C under the atmospheric pressure. The Ni/La₂O₃–ZrO₂ catalysts show excellent catalytic performance and anti-carbon property, which will be of great prospects for catalytic CO₂ reforming of COG in the future.     

Hydrogen production by steam reforming of ethanol over mesoporous Ni–Al2O3–ZrO2 xerogel catalysts: Effect of Zr/Al molar ratio

A series of mesoporous Ni–Al₂O₃–ZrO₂ xerogel catalysts (denoted as Ni-AZ-X) with different Zr/Al molar ratio (X) were prepared by a single-step epoxide-driven sol–gel method, and they were applied to the hydrogen production by steam reforming of ethanol. The effect of Zr/Al molar ratio of Ni-AZ-X catalysts on their physicochemical properties and catalytic activities was investigated. Textural and chemical properties of Ni-AZ-X catalysts were strongly influenced by Zr/Al molar ratio. Surface area of Ni-AZ-X catalysts decreased with increasing Zr/Al molar ratio due to the lattice contraction of ZrO₂ caused by the incorporation of Al³⁺ into ZrO₂. Interaction between nickel oxide species and support (Al₂O₃–ZrO₂) decreased with increasing Zr/Al molar ratio through the formation of NiO–Al₂O₃–ZrO₂ composite structure. Acidity of reduced Ni-AZ-X catalysts decreased with increasing Zr/Al molar ratio due to the loss of acid sites of Al₂O₃ by the addition of ZrO₂. Acidity of Ni-AZ-X catalysts served as a crucial factor determining the catalytic performance in the steam reforming of ethanol; an optimal acidity was required for maximum production of hydrogen. Among the catalysts tested, Ni-AZ-0.2 (Zr/Al = 0.2) catalyst with an intermediate acidity exhibited the best catalytic performance in the steam reforming of ethanol.     

Preparation of Ni–Cu/Mg/Al catalysts from hydrotalcite-like compounds for hydrogen production by steam reforming of biomass tar

Ni–Cu/Mg/Al bimetallic catalysts were prepared by the calcination and reduction of hydrotalcite-like compounds containing Ni²⁺, Cu²⁺, Mg²⁺, and Al³⁺, and tested for the steam reforming of tar derived from the pyrolysis of biomass at low temperature. The characterizations with XRD, STEM-EDX, and H₂ chemisorption confirmed the formation of Ni–Cu alloy particles. The Ni–Cu/Mg/Al bimetallic catalyst with the optimum composition of Cu/Ni = 0.25 exhibited much higher catalytic performance than the corresponding monometallic Ni/Mg/Al and Cu/Mg/Al catalysts in the steam reforming of tar in terms of activity and coke resistance. The catalyst gave almost total conversion of tar even at temperature as low as 823 K. This high performance was related to the higher metal dispersion, larger amount of surface active sites, higher oxygen affinity, and surface modification caused by the formation of small Ni–Cu alloy particles. In addition, the Ni–Cu/Mg/Al catalyst showed better long-term stability than the Ni/Mg/Al catalyst. No obvious aggregation and structural change of the Ni–Cu alloy particles were observed. The coke deposition on the Ni–Cu/Mg/Al catalyst was approximately ten times smaller than that on the Ni/Mg/Al catalyst, indicating good coke-resistance of the Ni–Cu alloy particles.     

Methane reforming with CO2 using nickel catalysts supported on yttria-doped SBA-15 mesoporous materials via sol–gel process

A series of mesoporous yttrium (Y)-containing SBA-15 (mesoporous silica of Santa Barbara Amorphous type material) prepared using a sol–gel method with various Y/Si molar ratios was investigated as the supporting material of nickel (Ni) catalysts for the methane reforming with CO₂. The highly ordered hexagonal structure of SBA-15 was well-retained after the incorporation of yttrium at the molar ratio of Y/Si (0.04). The presence of yttrium in the framework of SBA-15 in Ni catalysts effectively enhanced the formation of the Ni metallic particles with small size. It also significantly promoted the reduction of NiO due to the oxygen vacancies on the surface of the yttrium-containing SBA-15 supports, and the high mobility of the surface oxygen species. All yttrium-containing nickel catalysts were effective for the methane reforming with CO₂. The supported Ni catalyst with Y/Si molar ratio of 0.04 exhibited the highest activity, which was due to its highly ordered mesoporous structure, large pore diameter and small metallic metal size.     

Characterization and activity test of commercial Ni/Al2O3, Cu/ZnO/Al2O3 and prepared Ni–Cu/Al2O3 catalysts for hydrogen production from methane and methanol fuels

In this study, methane and methanol steam reforming reactions over commercial Ni/Al₂O₃, commercial Cu/ZnO/Al₂O₃ and prepared Ni–Cu/Al₂O₃ catalysts were investigated. Methane and methanol steam reforming reactions catalysts were characterized using various techniques. The results of characterization showed that Cu particles increase the active particle size of Ni (19.3 nm) in Ni–Cu/Al₂O₃ catalyst with respect to the commercial Ni/Al₂O₃ (17.9). On the other hand, Ni improves Cu dispersion in the same catalyst (1.74%) in comparison with commercial Cu/ZnO/Al₂O₃ (0.21%). A comprehensive comparison between these two fuels is established in terms of reaction conditions, fuel conversion, H₂ selectivity, CO₂ and CO selectivity. The prepared catalyst showed low selectivity for CO in both fuels and it was more selective to H₂, with H₂ selectivities of 99% in methane and 89% in methanol reforming reactions. A significant objective is to develop catalysts which can operate at lower temperatures and resist deactivation. Methanol steam reforming is carried out at a much lower temperature than methane steam reforming in prepared and commercial catalyst (275–325 °C). However, methane steam reforming can be carried out at a relatively low temperature on Ni–Cu catalyst (600–650 °C) and at higher temperature in commercial methane reforming catalyst (700–800 °C). Commercial Ni/Al₂O₃ catalyst resulted in high coke formation (28.3% loss in mass) compared to prepared Ni–Cu/Al₂O₃ (8.9%) and commercial Cu/ZnO/Al₂O₃ catalysts (3.5%).     

Synthesis gas production from CO2 reforming of methane over Ni–Ce/SiO2 catalyst: The effect of calcination ambience

Ni–Ce/SiO₂ catalysts were prepared by calcination under Ar, CO₂, O₂ and H₂ ambience, and applied in CO₂ reforming of methane for synthesis gas production. BET, XRD, XPS, TPR, SEM, TEM and TPH techniques were employed to characterize the fresh and used catalysts. Highly dispersed nickel oxides bearing stronger interaction with SiO₂ prevented the metal sintering. The formation of reactive carbon species on Ni–Ce/SiO₂ catalyst calcined under Ar ambience effectively promoted the carbon elimination and kept the catalyst more stable. Nevertheless, the oxygen storage capacity of CeO₂ might partly lose on Ni–Ce/SiO₂ calcined under H₂ ambience. As a result, the inhibition of carbon elimination and the deposition of inert carbon were responsible for its partial deactivation.     

Effect of preparation method of mesoporous Ni–Al2O3 catalysts on their catalytic activity for hydrogen production by steam reforming of liquefied natural gas (LNG)

Mesoporous Ni–Al₂O₃ catalysts were prepared by impregnation method (NiAl-IP), co-precipitation method (NiAl-CP), and sequential precipitation method (NiAl-SP) for use in hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of preparation method of mesoporous Ni–Al₂O₃ catalysts on their catalytic activity for steam reforming of LNG was investigated. Physicochemical properties of Ni–Al₂O₃ catalysts were strongly influenced by the preparation method of Ni–Al₂O₃ catalysts. Surface area, pore volume, and average pore size of Ni–Al₂O₃ catalysts decreased in the order of NiAl-SP > NiAl-CP > NiAl-IP. Nickel species strongly interacted with Al₂O₃ supports through the formation of nickel aluminate phase. Surface nickel aluminate phase of Ni–Al₂O₃ catalysts was readily reduced after the reduction process, while bulk nickel aluminate phase of NiAl-CP catalyst was hardly reducible. Nickel dispersion and nickel surface area of Ni–Al₂O₃ catalysts decreased in the order of NiAl-SP > NiAl-CP > NiAl-IP. Among the catalysts tested, NiAl-SP catalyst with the highest nickel surface area showed the best catalytic performance in the steam reforming of LNG. Furthermore, finely dispersed nickel species in the NiAl-SP catalyst efficiently suppressed the carbon deposition during the reaction.     

Synthesis gas production in the combined CO2 reforming with partial oxidation of methane over Ce-promoted Ni/SiO2 catalysts

A series of nickel-based catalyst supported on silica (Ni/SiO₂) with different loading of Ce/Ni (molar ratio ranging from 0.17 to 0.84) were prepared using conventional co-impregnation method and were applied to synthesis gas production in the combination of CO₂ reforming with partial oxidation of methane. Among the cerium-containing catalysts, the cerium-rich ones exhibited the higher activity and stability than the cerium-low ones. The temperature-programmed reduction (TPR) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS) analysis revealed that the addition of CeO₂ reduced the chemical interaction between Ni and support, resulting in an increase in reducibility and dispersion of Ni. Over NiCe-x/SiO₂ (x = 0.17, 0.50, 0.67, 0.84) catalysts, the reduction peak in TPR profiles shifted to the higher temperature with increasing Ce/Ni molar ratio, which was attributed to the smaller metallic nickel size of the reduced catalysts. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) for the post-reaction catalysts confirmed that the promoter retained the metallic nickel species and prevented the metal particle growth at high reaction temperature. The NiCe-0.84/SiO₂ catalyst with small Ni particle size exhibited the stable activity with the constant H₂/CO molar ratio of 1.2 during 6-h reaction in the combination of CO₂ reforming with partial oxidation of methane at 850 °C and atmospheric pressure.     

Role of CeO2/ZrO2 mole ratio and nickel loading for steam reforming of n-butanol using Ni–CeO2–ZrO2–SiO2 composite catalysts: A reaction mechanism

This study presents steam reforming of n-butanol to synthesis gas using high surface area mesoporous Ni–CeO₂–ZrO₂–SiO₂ composite catalysts. The reaction proceeds through a combination of dehydrogenation, dehydration, and cracking reactions with propanal, butanal, and C₂–C₄ hydrocarbons as intermediate compounds. The ceria forms a solid solution with zirconia, promotes dispersion of nickel, and enhances oxygen storage/release capacity. The carbon conversion to synthesis gas (CCSG) and hydrogen yield are thus enhanced with increasing CeO₂/ZrO₂ mole ratio up to 1:2 and decreased slightly for higher mole ratios. The CCSG and hydrogen yield are also boosted by increasing the amount of nickel in the catalyst up to 20 wt%. 1:2 CeO₂/ZrO₂ mole ratio and 20 wt% nickel content are thus deliberated as optimum. The optimum catalyst exhibits stable catalytic performance for about 30 h time-on-stream. The study further presents the effect of temperature and steam/carbon mole ratio on n-butanol steam reforming.     

Renewable hydrogen production from steam reforming of glycerol by Ni–Cu–Al,Ni–Cu–Mg,Ni–Mg catalysts

H₂ production from glycerol steam reforming by the Ni–Cu–Al, Ni–Cu–Mg, Ni–Mg catalysts was evaluated experimentally in a continuous flow fixed-bed reactor under atmospheric pressure within a temperature range from 450 to 650 °C. The catalysts were synthesized by the co-precipitation methods, and characterized by the elemental analysis, BET, XRD and SEM. The GC and FTIR were applied to analyze the products from steam reforming of glycerol. The coke deposited on the catalysts was measured by TGA experiments during medium temperature oxidation. The results showed that glycerol conversion and H₂ production were increased with increasing temperatures, and glycerol decomposition was favored over its steam reforming at low temperatures. The Ni–Cu–Al catalyst containing NiO of 29.2 wt%, CuO of 31.1 wt%, Al₂O₃ of 39.7 wt% performed high catalytic activity, and the H₂ selectivity was found to be 92.9% and conversion of glycerol was up to 90.9% at 650 °C. The deactivation of catalysts due to the formation and deposition of coke was observed. An improved iterative Coats–Redfern method was used to evaluate the non-isothermal kinetic parameters of coke removal from catalysts, and the results showed the reaction order of n = 1 and 2 in the Fn nth order reaction model predicted accurately the main phase in the coke removal for the regeneration of Ni–Mg and Ni–Cu–Al catalysts, respectively.     

CO2 reforming of CH4 over rare earth elements functionalized mesoporous Ni–Ln (Ln = Ce,La, Sm,Pr)–Al–O composite oxides

A series of rare earth elements functionalized mesoporous Ni–Ln (Ln = Ce, La, Sm, Pr)–Al–O composite oxides were originally designed and facilely synthesized via one-pot evaporation induced self-assembly (EISA) strategy. These mesoporous materials with outstanding thermal stability were investigated as the catalysts for the CO₂ reforming of CH₄, performing excellent catalytic activities and long-term catalytic stabilities. The “confinement effect” of the mesoporous framework matrixes contributed to stabilizing the Ni nanoparticles during the process of reaction; therefore, the serious thermal sintering of the Ni nanoparticles under severe reduction and reaction conditions was suppressed to some degree, accounting for the long catalytic stability of these mesoporous catalysts. The modification of the rare earth elements (Ce, La, Sm, Pr) played crucial roles in promoting the catalytic activities and reducing the carbon deposition. Besides, the presence of the rare earth elements also significantly influenced the distribution of the carbon species deposited over the spent catalysts. Hereby, these mesoporous Ni–Ln (Ln = Ce, La, Sm, Pr)–Al–O composite oxides promised a group of novel and stable catalyst candidates for carbon dioxide reforming of methane.     

Catalytic steam reforming of glycerol over Ni–La2O3–CeO2/SBA-15 catalyst for stable hydrogen-rich gas production

Ni-based catalysts (Ni, Ni–La₂O₃, and Ni–La₂O₃–CeO₂) on mesoporous silica supports (SBA-15 and KIT-6) were prepared by an incipient wetness impregnation and tested in glycerol steam reforming (GSR) for hydrogen-rich gas production. The catalysts were characterized by the N₂-physisorption, TPD, X-ray diffraction (XRD), SEM-EDS, and TEM techniques. N₂-physisorption results of calcined catalysts highlight that adding of La₂O₃ increased surface area of the catalyst by preventing pore mouth plugging in SBA-15, which was frequently observed due to the growth of NiO crystals. A set of GSR experiments over the catalysts were performed in an up-flow continuous packed-bed reactor at 650 °C and atmospheric pressure. The highest hydrogen concentration of 62 mol% was observed with a 10%Ni–5%La₂O₃ –5%CeO₂/SBA-15 catalyst at a LHSV of 5.8 h⁻¹. Adding of CeO₂ to the catalyst appeared to increase catalytic stability by facilitating the oxidative gasification of carbon formed on/near nickel active sites of Ni–La₂O₃–CeO₂/SBA-15 and Ni–La₂O₃–CeO₂/KIT-6 catalyst during the glycerol steam reforming reaction.     

Effect of Ca,Ce or K oxide addition on the activity of Ni/SiO2 catalysts for the methane decomposition reaction

To increase the activity and stability of Ni/SiO₂ catalysts, a series of Ni–Ca, Ni–K and Ni–Ce promoted catalysts were prepared by successive impregnations. The textural properties, reducibility and catalytic performance in the methane decomposition reaction were investigated. The catalyst containing 30 wt.% Ni and 30 wt.% cerium oxide greatly increased the conversion of methane (90% of equilibrium value) and improved the stability, whereas the Ni–K and Ni–Ca were less active and stable than the Ni/SiO₂ catalyst. The results suggest that Ce addition prevents the sintering of nickel particles during reduction process maintaining a random distribution between the silica and cerium oxide improving the distribution and migration of deposited carbon.