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.     

Ethanol steam reforming on Ni/Al-SBA-15 catalysts: Effect of the aluminium content

A series of Ni catalysts supported on Al-SBA-15 mesoporous materials (Si/Al = 20, 60, 140, 240, ∞) was prepared and tested in ethanol steam reforming. The catalysts were characterized by XRD, H₂-TPR, NH₃-TPD, TEM, ICP-AES, ²⁷Al-MAS-NMR and N₂-sorption measurements. It was found that the incorporation of Al atoms into SBA-15 structure is responsible for the formation of catalyst acid sites, an increase of the size of nickel species and stronger metal-support interaction between Ni and Al-SBA-15 carrier. Regarding ethanol steam reforming, catalysts with higher Al content keep ethanol conversion along time. However, Ni/Al-SBA-15 catalysts produce larger amounts of ethylene and coke, with slightly lower hydrogen selectivity than Ni/SBA-15. This is the consequence of ethanol dehydration in Ni/Al-SBA-15 acid sites, while ethanol dehydrogenation mechanism predominates in Ni/SBA-15 catalyst.     

Current advances in syngas (CO + H2) production through bi-reforming of methane using various catalysts: A review

Today, bi - reforming of methane is considered as an emerging replacement for the generation of high-grade synthesis gas (H₂:CO = 2.0), and also as an encouraging renewable energy substitute for fossil fuel resources. For achieving high conversion levels of CH₄, H₂O, and CO₂ in this process, appropriate operation variables such as pressure, temperature and molar feed constitution are prerequisites for the high yield of synthesis gas. One of the biggest stumbling blocks for the methane reforming reaction is the sudden deactivation of catalysts, which is attributed to the sintering and coke formation on active sites. Consequently, it is worthwhile to choose promising catalysts that demonstrate excellent stability, high activity and selectivity during the production of syngas. This review describes the characterisation and synthesis of various catalysts used in the bi-reforming process, such as Ni-based catalysts with MgO, MgO–Al₂O₃, ZrO_2, CeO₂, SiO₂ as catalytic supports. In summary, the addition of a Ni/SBA-15 catalyst showed greater catalytic reactivity than nickel celites; however, both samples deactivated strongly on stream. Ce-promoted catalysts were more found to more favourable than Ni/MgAl₂O₄ catalyst alone in the bi-reforming reaction due to their inherent capability of removing amorphous coke from the catalyst surface. Also, Lanthanum promoted catalysts exhibited greater nickel dispersion than Ni/MgAl₂O₄ catalyst due to enhanced interaction between the metal and support. Furthermore, La₂O₃ addition was found to improve the selectivity, activity, sintering and coking resistance of Ni implanted within SiO₂. Non-noble metal-based carbide catalysts were considered to be active and stable catalysts for bi-reforming reactions. Interestingly, a five-fold increase in the coking resistance of the nickel catalyst with Al₂O₃ support was observed with incorporation of Cr, La₂O₃ and Ba for a continuous reaction time of 140 h. Bi-reforming for 200 h with Ni-γAl₂O₃ catalyst promoted 98.3% conversion of CH₄ and CO₂ conversion of around 82.4%. Addition of MgO to the Ni catalyst formed stable MgAl₂O₄ spinel phase at high temperatures and was quite effective in preventing coke formation due to enhancement in the basicity on the surface of catalyst. Additionally, the distribution of perovskite oxides over 20 wt % silicon carbide-modified with aluminium oxide supports promoted catalytic activity. NdCOO₃ catalysts were found to be promising candidates for longer bi-reforming operations.     

Ni/SBA-15 catalysts for hydrogen production by ethanol steam reforming: Effect of nickel precursor

The effect of nickel precursor on Ni/SBA-15 catalysts was studied in ethanol steam reforming (ESR) for hydrogen production. These catalysts were prepared via incipient-wetness impregnation method using nickel nitrate and nickel citrate precursors, respectively (denoted as Ni/SBA-15(N) and Ni/SBA-15(C), respectively), and characterized by various techniques including H₂-TPR, XRD, TEM and TG. It was found that the use of nickel citrate precursor, compared to nickel nitrate precursor, could greatly strengthen the NiO-support interaction and promote the homogeneous distribution of nickel species, to obtain the small nickel particles with high dispersion. After a 25 h time-on-stream test, much lower coke deposition was formed over Ni/SBA-15(C) than Ni/SBA-15(N). Moreover, NiC_x species had be found over the used Ni/SBA-15(C), in which the carbon could be removed easily at lower temperature to exposure the active Ni sites; While carbon nanofibers with regular graphite-structure were the primary coke species over the spent Ni/SBA-15(N), which was difficultly remove and thus covered the active Ni sites easily. Due to these, Ni/SBA-15(C) displayed the higher catalytic activities and better stabilities in ESR than Ni/SBA-15(N). In summary, nickel citrate is an excellent precursor for the preparation of Ni/SBA-15 catalysts with high dispersion and strong interaction.     

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.     

Ceria-promoted Ni@Al2O3 core-shell catalyst for steam reforming of acetic acid with enhanced activity and coke resistance

A series of Ni@Al₂O₃ core-shell catalysts with ceria added to the surface of Ni nanoparticles or inside the alumina shell were prepared, and the effect of ceria addition on the performance of the catalyst in the steam reforming of acetic acid was investigated. The prepared catalysts were characterized by BET, XRD, HRTEM, H₂-TPR and DTG. The addition of ceria to the surface of nickel nanoparticles greatly enhanced the activity of catalyst owing to the presence of the mobile oxygen, which migrated from the ceria lattice. Among the prepared catalysts, the Ni@Al10Ce catalyst showed the highest activity with a conversion of acetic acid up to 97.0% even at a low temperature (650 °C). The molar ratio of CO₂/CO was also improved due to the oxidation of CO by the mobile oxygen into CO₂. The coke formation on the core-shell catalysts was significantly inhibited by the addition of ceria to the surface of nickel nanoparticles due to the oxidation of carbon species by the mobile oxygen in the ceria lattice. However, the Ni@Al10Ce-a catalyst with ceria added to the alumina shell showed a low activity and the formation of a large amount of coke. It is suggested that only the ceria in close to the Ni surface has the promoting effect on the catalytic performance of the Ni@Al₂O₃ catalyst in the steam reforming of acetic acid.     

A review on ethanol steam reforming for hydrogen production over Ni/Al2O3 and Ni/CeO2 based catalyst powders

Hydrogen is contemplated as an alternative clean fuel for the future. Ethanol steam reforming (ESR) is a carbon-neutral, sustainable, green hydrogen production method. Low cost Ni/Al₂O₃ and Ni/CeO₂ powder catalysts demonstrate high ESR activity. However, acidic nature of Al₂O₃ and instability of CeO₂ lead to deactivation of the catalysts easily. This article examines the research articles published on the modification of Ni by various noble and non-noble metals and on alteration of the supports by different metal oxides in detail and their effect on ESR all through 2000–2021. The ESR reaction mechanisms on Ni/Al₂O₃ and Ni/CeO₂ powder catalysts and basic thermodynamics for different possible reactions and H₂ yield are explored. Manipulation of catalyst morphology (surface area and particle size) via preparation method, selection of active metal promoter and support modifier are found to be significantly important for H₂ production and minimizing carbon deposition on catalysts.     

Effects of noble metal-doping on Ni/La2O3–ZrO2 catalysts for dry reforming of coke oven gas

A series of noble metal (Ru, Pd, Ag) doped Ni catalysts supported on La₂O₃–ZrO₂ mixed oxide were prepared using the sol–gel method and evaluated for use in dry reforming of coke oven gas (COG). The catalysts were investigated by means of N₂ adsorption–desorption, XRD, H₂-TPR, TPH, TEM and TG–DSC. TPH analysis revealed that two carbonaceous species formed on the used catalysts and that the low-temperature carbon species was sufficiently active for the reforming reaction. TEM observations indicated that highly dispersed and small metal particles were formed, suppressing coke deposition and improving catalytic performance. The test results indicated that the addition of trace amounts of noble metals effectively promotes catalytic activity. The 0.1Ru–10Ni/8LZ catalyst showed the highest performance among the bimetallic catalysts, because of the strong synergetic effect between Ru and Ni via the formation of a Ru–Ni alloy, which will be promising catalysts in the catalytic dry reforming of COG.     

Development of highly effective supported nickel catalysts for pre-reforming of liquefied petroleum gas under low steam to carbon molar ratios

The pre-reforming of commercial liquefied petroleum gas (LPG) was investigated over Ni–CeO₂ catalysts at low steam to carbon (S/C) molar ratios less than 1.0. It was found that the catalytic activity and selectivity depended strongly on the nature of the support and the interaction between Ni and CeO₂. The Ni–CeO₂/Al₂O₃ catalysts, which were prepared by impregnating boehmite (AlOOH) with an aqueous solution of cerium and nickel nitrates, exhibited the optimal catalytic activity and remarkable stability for the steam reforming of LPG in the temperature range of 275–375 °C. The effects of CeO₂ loading, reaction temperature and S/C ratio on the catalytic behavior of the Ni–CeO₂/Al₂O₃ catalysts were discussed in detail. The results showed that the catalysts with 10 wt.% CeO₂ had the highest catalytic activity, and higher S/C ratios contributed to LPG reforming and the methanation of carbon oxides and hydrogen. The XRD and H₂-TPR analyses revealed that the strong interaction between Ni and CeO₂ resulted in the formation of CeAlO₃ in the Ni–CeO₂/Al₂O₃ catalysts reduced. The stability tests of 15Ni–10CeO₂/Al₂O₃ catalyst at 350 °C indicated that the catalyst was stable, and the stability could be enhanced by increasing S/C ratio.     

Highly active Nd-promoted Ni@Al2O3 core-shell catalyst for steam reforming of acetic acid: Insights of the remarkable coke resistance

Aiming at enhancing the coke resistance of Ni-based catalysts, the Nd-doped Ni@A₂O₃ core-shell catalysts were prepared and their catalytic performance was evaluated in the steam reforming of acetic acid (SRAA). The catalysts were characterized by BET, XRD, XRF, HRTEM, H₂-TPR, NH₃-TPD, and DTG. The catalytic performance was greatly enhanced by the incorporation of Nd, with decreased yields of CO, CH₄, and acetone, increased yield of CO₂, and remarkable carbon resistance. The decoking behavior of the spent catalyst was elucidated by H₂O¹⁸-TSD. A low reaction temperature facilitates the formation of amorphous carbon, leading to catalyst deactivation. The decoking ability of the catalyst is greatly improved by the Nd incorporation but is also catalyzed by the exposed Ni surface. The Ni0.01Nd@Al catalyst greatly balanced the exposed Ni surface and the mobile lattice oxygen, showing the highest catalytic activity, lowest coke deposition, and superb decoking ability.     

Catalysts for H2 production using the ethanol steam reforming (a review)

This review aims to provide an overview of the main catalytic studies of H₂ production by ethanol steam reforming (ESR). The reaction is endothermic and produces H₂, CO₂, CH₄, CO and coke. The conversion and H₂ selectivity of these products depended greatly of the physicochemical properties of the catalysts, active metal, promoters, temperature, long-term reaction, water/ethanol ratio, space velocity, contact time, and presence of O₂. Initial total conversion has been reported in all catalysts evaluated between 300 and 850 °C. The noble catalysts with high selectivity to H₂ (more than 80%) were: Rh, Ru, Pd and Ir and non-noble metal catalysts were: Ni, Co and Cu. The support materials include CeO₂, ZnO, MgO, Al₂O₃, zeolites-Y, TiO₂, SiO₂, La₂O₂CO₃, CeO₂–ZrO₂ and hydrotalcites. The impregnation method produced the best noble metal catalysts in terms of selectivity and conversion. The decrease of coke was related with the presence of basic sites on the support.     

Catalytic steam reforming of complex gasified biomass tar model toward hydrogen over dolomite promoted nickel catalysts

The complex mixture of gasified tar model (phenol, toluene, naphthalene, and pyrene) was steam reformed for hydrogen production over 10 wt% nickel based catalysts. The catalysts were prepared by co-impregnation method with dolomite promoter and various oxide supports (Al₂O₃, La₂O₃, CeO₂, and ZrO₂). Steam reforming was carried out at 700 °C at atmospheric pressure with steam to carbon molar ratio of 1 and gas hourly space velocity of 20 L/h·g_cat. The catalysts were characterised for reducibility, basicity, crystalline, and total surface area properties. Dolomite promoter strengthened the metal-support interaction and basicity of catalyst. The Ni/dolomite/La₂O₃ (NiDLa) catalyst with mesoporous structure (26.42mn), high reducibility (104.42%), and strong basicity (5.56 mmol/g) showed superior catalytic performance in terms of carbon conversion to gas (77.7%), H₂ yield (66.2%) and H₂/CO molar ratio (1.6). In addition, the lowest amount of filamentous coke was deposited on the spent NiDLa after 5 h.     

Synergistic effects of ZrO2 crystallite islands and high dispersion of active Ni0 nanoparticles on CH4/CO2 reforming reaction

A series of mesoporous 9NixZrO₂/SBA-15 were prepared by coupled self-assembly and evaluated for CO₂/CH₄ reforming, which revealed that high activity and stability of 9Ni9ZrO₂/SBA-15 correlated closely with the synergistic effects of ZrO₂ crystallite islands and high dispersion of active Ni⁰ nanoparticles which promote adsorption of CO₂ and facilitated high efficient conversion of residual CH_x species. The XRD, O₂-TPD, HAADF-Zr mapping and UV–vis DRS analysis verified the existence of stable ZrO₂ crystallites and the formation of surface oxygen vacancies. The XPS and HRTEM images of 9NixZrO₂/SBA-15 before and after CH₄/CO₂ reforming proclaimed the distribution of catalyst surface active species, synergistic action between CO₂ and vacancies as well as formation character of CNTs. A catalytic mechanism of CH₄/CO₂ conversion into CO/H₂ has been put forward. The allotropes of coke and physical properties of catalysts were systematically analyzed by TG/DTG, first derivative XAES, H₂-TPR, N₂-physisorption and FT-IR.     

Biohydrogen production by gas phase reforming of glycerine and ethanol mixtures

In this paper the steam reforming of bioalcohols over Ni and Pt catalysts supported on bare Al₂O₃ and La₂O₃ and CeO₂-modified Al₂O₃ to produce H₂ was studied. Catalytic activity results showed that the glycerine and the intermediate liquid products may hinder the ethanol adsorption on metal active sites of the catalysts, especially at temperatures below 773 K. In fact, ethanol conversion was lower than glycerine conversion in the steam reforming reaction at low temperatures. H₂ chemisorption revealed that La₂O₃ doping of the Ni/Al₂O₃ catalyst improved the metal dispersion providing a better behaviour to the Ni/Al₂O₃-O2 catalyst towards H₂ production. In the case of Pt catalysts, the good reducibility and the H₂ spillover effect provided to the Pt/Al₂O₃-O1 catalyst the capacity to produce higher H₂ yields.     

Y2O3-promoted NiO/SBA-15 catalysts highly active for CO2/CH4 reforming

A series of Y₂O₃-promoted NiO/SBA-15 (9 wt% Ni) catalysts (Ni:Y weight ratio = 9:0, 3:1, 3:2, 1:1) were prepared using a sol–gel method. The fresh as well as the catalysts used in CO₂ reforming of methane were characterized using N₂-physisorption, XRD, FT-IR, XPS, UV, HRTEM, H₂-TPR, O₂-TPD and TG techniques. The results indicate that upon Y₂O₃ promotion, the Ni nanoparticles are highly dispersed on the mesoporous walls of SBA-15 via strong interaction between metal ions and the HO–Si-groups of SBA-15. The catalytic performance of the catalysts were evaluated at 700 °C during CH₄/CO₂ reforming at a gas hourly space velocity of 24 L g_cat⁻¹ h⁻¹(at 25 ^°C and 1 atm) and CH₄/CO₂molar ratio of 1. The presence of Y₂O₃ in NiO/SBA-15 results in enhancement of initial catalytic activity. It was observed that the 9 wt% Y–NiO/SBA-15 catalyst performs the best, exhibiting excellent catalytic activity, superior stability and low carbon deposition in a time on stream of 50 h.     

The evaluation of autothermal methane reforming for hydrogen production over Ni/CeO2 catalysts

Nanocrystalline Ni/CeO₂ catalysts with various loadings of Ni (10, 15, 20, and 25%) were synthesised by a facile solvent deficient precipitation method for methane autothermal reforming process. The characterisation techniques such as XRD, BET, TPH, H₂-TPR were carried out on fresh and spent samples to investigate the catalytic properties of the Ni/CeO₂. On the basis of characterisation results, the 20% Ni/CeO₂ performs the best activity among the catalysts with different Ni contents. The optimal reaction conditions for autothermal methane reforming has been investigated by evaluating the effect of reaction parameters including the reactivity temperature, the gas hourly space velocity (GHSV) and H₂O/CH₄ (S/C) and O₂/CH₄ (O/C) molar ratios. The stability of 20 wt% Ni/CeO₂ catalyst at 700 °C is examined for 20 h on-stream reaction. It reveals that the methane conversion starts a graduate decrease trend from the second 10 h, which is found to be because of the sintering of Ni nanoparticles by TPH and BET analysis.     

Biohydrogen synthesis from catalytic steam gasification of furniture waste using nickel catalysts supported on modified CeO2

Present study evaluated the catalytic steam gasification of furniture waste to enhance the biohydrogen production. To do this, 10 wt% nickel loaded catalysts on the variety of supports (Al₂O₃, CeO₂, CeO₂-La₂O₃, and CeO₂–ZrO₂) were prepared by the novel solvent deficient method. The hydrogen selectivity (vol%) order of the catalysts was achieved as Ni/CeO₂–ZrO₂>Ni/CeO₂>Ni/Al₂O₃?Ni/CeO₂-La₂O₃. The best catalytic activity of Ni/CeO₂–ZrO₂ catalyst (~82 vol % H₂ at 800 °C) was ascribed to the smaller size of nickel crystals, finely dispersed Ni on the catalyst surface, and Ce_1-xZr_xO_2-δ solid solution. The role of Ce_1-xZr_xO_2-δ solid solution in Ni/CeO₂–ZrO₂ catalyst was observed as bi-functional; acceleration of water-gas-shift and oxidation of carbon reaction. The high resistance of Ni/CeO₂–ZrO₂ towards the coke formation showed its potential to establish a cost-effective commercial-scale biomass steam gasification process. This study is expected to provide a promising solution for the disposal of furniture wastes for production of clean energy (biohydrogen).     

Synthesis, characterization and catalytic performances of Ce-SBA-15 supported nickel catalysts for methane dry reforming to hydrogen and syngas

A series of Ce-incorporated SBA-15 mesoporous materials were synthesized through direct hydrothermal synthesis method and further impregnated with 12 wt.% Ni. The samples were characterized by ICP-AES, XRD, N₂ physisorption, XPS, TPR, H₂ chemisorption, TGA, temperature-programmed hydrogenation (TPH) and TEM measurements. The low-angle XRD and N₂ physisorption results showed the Ce successfully incorporated into the framework of SBA-15. The catalytic properties of these catalysts were investigated in methane reforming with CO₂. The Ce/Si molar ratio had a significant influence on the catalytic performance. The highest catalytic activity and long-term stability were obtained over the Ni/Ce-SBA-15 (Ce/Si = 0.04) sample. The improved catalytic behavior could be attributed to the cerium impact in the framework of SBA-15, where cerium promoted the dispersion of nano-sized Ni species and inhibited the carbon formation. In comparison with the effect of CeO₂ crystallites in SBA-15, cerium in the framework of SBA-15 promoted the formation of the nickel metallic particles with smaller size. The XRD and TGA results exhibited that carbon deposition was responsible for activity loss of Ni/SBA-15 and Ni/Ce-SBA-15 (Ce/Si = 0.06) catalysts. TEM results showed that the hexagonal mesopores of SBA-15 were still kept intact after reaction and the pore walls of SBA-15 prevented the aggregation of nickel.     

Assessing the potential of xNi-yMg-Al2O3 catalysts prepared by EISA-one-pot synthesis towards CO2 methanation: An overall study

Mesoporous xNi-yMg-Al₂O₃ catalysts prepared by combined evaporation induced self-assembly (EISA) and one-pot techniques were tested in CO₂ methanation reaction. All calcined/reduced materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), N₂ physisorption, thermogravimetric analysis (TGA), CO₂ adsorption, H₂ temperature programmed reduction (H₂-TPR) and transmission electron microscopy (TEM). The effects of Mg and Ni loadings on the catalysts properties and performances were systematically studied. Higher Mg contents enhanced methanation performances due to more favourable metallic interactions between the Ni, Mg and Al species. In addition, higher Ni contents led to better selectivity to CH₄ by enhancing methane formation that involves H₂ dissociation on Ni⁰ sites. The mesoporous 5Ni–Al₂O₃ catalyst obtained by the EISA-one-pot technique was significantly more active than silica-based catalysts with same 5 wt% Ni content supported on USY zeolite and SBA-15. Moreover, the performances of the most promising 15Ni–7Mg–Al₂O₃ mesoporous material were similar to those of a commercial 25Ni/γ-Al₂O₃ catalyst in spite of its reduced nickel content.     

Effects of synthesis route on the performance of mesoporous ceria-alumina and ceria-zirconia-alumina supported nickel catalysts in steam and autothermal reforming of diesel

Decline in catalyst performance due to coke deposition is the main problem in diesel steam (SR) and autothermal reforming (ATR) reactions. Good redox potential and strong interaction of CeO₂ with nickel increase activity and coke resistivity of Ni/Al₂O₃ catalysts. In this study, mesoporous Al₂O₃, CeO₂/Al₂O₃, and CeO₂/ZrO₂/Al₂O₃ supported nickel catalysts were successfully synthesized. The highest hydrogen yield, 97.7%, and almost no coke deposition were observed with CeO₂/ZrO₂/Al₂O₃ catalyst (Ni@8CeO₂-2ZrO₂-Al₂O₃-EISA) in SR reaction. The second highest hydrogen yield, 91.4%, was obtained with CeO₂/Al₂O₃ catalyst (Ni@10CeO₂-Al₂O₃-EISA) with 0.3 wt% coke deposition. Presence of ZrO₂ prevented the transformation of cubic CeO₂ into CeAlO₃, which enhanced water gas shift reaction (WGSR) activity. Ni@10CeO₂-Al₂O₃-EISA did not show any decline in activity in a long-term performance test. Higher CeO₂ incorporation (20 wt%) caused lower steam reforming activity. Change of synthesis route from one-pot to impregnation for the CeO₂ incorporation decreased the number of acid sites, limiting cracking reactions and causing a significant drop in hydrogen production.