Activity In Dry Reforming Of Methane Research Articles

Promoted coke resistance of Ni by surface carbon for the dry reforming of methane.

Dry reforming of methane (DRM) is an efficient process to transform methane and carbon dioxide to syngas. Nickel could show good catalytic activity for DRM, whereas the deactivation of nickel surfaces by the formation of inert carbon structures is inevitable. In this study, we carry out a detailed investigation of the evolution and catalytic performance of the carbon-covered surface structure on Ni(100) with a combined density functional theory and microkinetic modeling approach. The results suggest that the pristine Ni(100) surface is prone to carbon deposition and accumulation under reaction conditions. Further studies show that over this carbon-covered reconstructed Ni(100) surface, a carbon-based Mars-van-Krevelen mechanism would be favored, and the activity and coke resistance is promoted. This surface state and reaction mechanism were rarely reported before and would provide more insights into the DRM process under real reaction conditions and would help design more stable Ni catalysts.

Ni, Co and Ni-Co-Modified Tungsten Carbides Obtained by an Electric Arc Method as Dry Reforming Catalysts

Dry reforming of methane (DRM), to produce synthesis gas, is one of the most important chemical reactions used for the industrial production of hydrogen and leads to the synthesis of hydrocarbons (liquid fuels) and other valuable products. A cost-effective alternative to active and stable noble metal DRM catalysts, with comparable catalytic performance, can be composite materials based on nickel, cobalt and transition metal carbides. In this line, the present work proposes a non-standard way to obtain dry reforming catalysts of Ni, Co and Ni-Co-modified tungsten carbide (WC) produced by an electric arc method. Different amounts of nickel, cobalt and their mixtures were deposited on tungsten carbide by deposition-precipitation with NaOH (DP) and incipient wetness impregnation (IWI) methods. The resulting materials were characterized by N2 adsorption-desorption, transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy, and their performance was evaluated in DRM. The composition and preparation method of catalysts predetermined their structural, textural and electronic properties, playing a decisive role in their activity for DRM. DP-prepared 20%Ni/WC material remained resistant to oxidation, both that of the active metal (nickel) and of the tungsten carbide, as well as to coking during DRM. This sample proved to be the most active and stable among all studied materials. Possibly, the resistance to oxidation and coking was due to a more efficient implementation of the oxidation/(re)carbonization cycle on the surface of this catalyst.

An in situ defect engineering approach for light-driven methane dry reforming over atomically distributed nickel

Dry reforming of methane economically converts methane and carbon dioxide into syngas (hydrogen and carbon monoxide) but requires high energy and often suffers from catalyst instability. Here, a surface-modulation strategy is demonstrated via decorating in situ defects on isolated nickel (Ni) atoms over La2O3 for boosting light-driven dry reforming of methane activity. Atomically dispersed 0.5Ni/La2O3 achieves a hydrogen evolution rate of 170.9 mol gNi−1 h−1. The reactivity is mainly attributed to photogenerated electrons, which overcome the limitations of a purely thermal system. The in situ generation of oxygen vacancies increases the initial-stage reactivity, where oxygen vacancies act as electron traps to accelerate charge separation and promote the adsorption/activation of reactants. The 0.5Ni/La2O3 catalyst exhibits strong inhibition of carbon coking and is sintering resistant, benefiting from the synergy between in situ oxygen vacancies and isolated nickel atoms.

Dry reforming of methane for syngas production over attapulgite-derived MFI zeolite encapsulated bimetallic Ni-Co catalysts

Dry reforming of methane (DRM) shows bright prospects for the treatment and value-added utilization of greenhouse gas, and catalyst inactivation has been a long-standing grand challenge for this process. Here, a catalyst of attapulgite-derived MFI (ADM) zeolite encapsulated Ni-Co alloys was synthesized using a one-pot method. Characterization results demonstrated that the Ni-Co alloys, which could be stably presentduring DRM process, favored the formation of electron-rich Ni metal sites and thus significantly enhanced C-H bond breaking ability. Meanwhile, the ADM zeolite not only firmly anchored metallic sites by pore or layer confinement, but also provided abundant CO2 adsorption/activation centers. These contributed to the improved anti-sinter and anti-coke ability as well as superior DRM activity of 10Ni1Co@ADM-0.1 catalyst. This work is expected to supply guidance for the development of clay-based metallic Ni catalysts and its application in DRM for syngas production.

Characteristics of (Sr0.92Y0.08)0.85Ti1-XNixO3-

Perovskite with A-site deficiency(A1-xBO3) is promising candidate due to introduction of oxygen vacancy for ionic conductivity and nano-sized exsolution of B component with metal phase for catalytic activity. In this study, Ni-doped Sr0.92Y0.08TiO3 perovskite has been investigated to improve the catalytic activity for CO2 dry internal reforming of methane in solid oxide fuel cells. (Sr0.92Y0.08)0.85Ti1-xNixO3- \U0001d6ff (x=0.05, 0.10, 0.15, 0.20) perovskite with A-site deficiency is prepared by pechini method and compared to stoichiometric Sr0.92Y0.08Ti1-xNixO3- \U0001d6ff (SYTN15) perovskite. The physical and physicochemical characteristics of the synthesized powders are analyzed by GC, XRD, BET, TEM, XPS, and TPO. (Sr0.92Y0.08)0.85Ti0.85Ni0.15O3- \U0001d6ff (SYTN(+)15) shows the highest methane conversion with 93% and carbon dioxide conversion with 86%. In addition, the SYTN(+)15 results to the lowest decreasing rate of the methane conversion with 1.86% drop for 50h. The SYTN(+)15 shows better catalytic performance by 10% for dry reforming of methane (DRM) comparing to the SYTN15. The cell performances of the SYTN(+)15 and the SYTN15 are 60.05mW/cm2 and 28.50mW/cm2, respectively. Consequently, A-site deficiency catalyst, SYTN(+)15 exhibits excellent catalytic activity for DRM and sufficient electrochemical property for SOFC anode materials.

Novel highly active and stable alumina-supported cobalt nitride catalyst for dry reforming of methane

Dry reforming of methane (DRM) was an important reaction for the utilization of two greenhouse gases (CH4 and CO2) as feedstocks. The development of non-precious metal catalysts has been widely studied for DRM in recent years. In the present study, non-precious metal nitrides Mo2N/γ-Al2O3, Co3Mo3N/γ-Al2O3 and Co4N/γ-Al2O3 were used as catalysts for DRM. Noticeably, the catalytic performance of monometallic nitride of Co4N was evaluated in DRM for the first time. It was found that the Co4N/γ-Al2O3 catalyst was more active and stable than Mo2N/γ-Al2O3 and Co3Mo3N/γ-Al2O3 in current DRM reaction, which was probably due to the fact that the contribution of noble metal type mechanism to DRM activity on Co4N/γ-Al2O3 was much more dominant than that on Mo2N/γ-Al2O3 and Co3Mo3N/γ-Al2O. Furthermore, it can show superior DRM performance over literature reported interstitial compounds (e.g. MoP, NiMoNx and Ni/Mo2C) and exhibit competitive activity in comparison with Ni-based or noble metal-based catalysts. Interestingly, the carbon deposition behavior of the Co4N/γ-Al2O3 catalyst was greatly dependent on WHSV and reaction temperature. The amount of carbon deposition increased with the decrease in WHSV, but decreased with the increase in temperature. This was probably due to the fact that the dissociation rates of CH4 and CO2 on the catalyst were directly related to these reaction conditions. Finding appropriate reaction conditions for matching between CH4 dissociation rate and CO2 dissociation rate as close as possible was of vital importance for the long-term stabilization of Co4N/γ-Al2O3 catalyst.

A short review on recent advancements of dry reforming of methane (DRM) over pyrochlores

Methane reforming with CO2 (DRM) is a recognized study in both research and industry sectors for the generation of syngas. The value-added products like higher alkanes and oxygenates from Fischer-Tropsch method requires syngas as a feedstock. Typically, DRM is an endothermic reaction and to attain high conversions of CH4 and CO2 to form syngas (H2 and CO), temperature range of 700–1000 °C is recommended. The most important parameter to be considered in DRM is the deactivation of catalyst due to coke deposition, however, this can be addressed by developing catalysts with strong metal support interactions (SMSI). A large number of articles based on Ni have been published, demonstrating its high catalytic activity for DRM as well as its limited commercial feasibility. Unfortunately, majority of Ni-based catalysts are ineffective in preventing coke deposition at temperatures above 700 °C. To reduce the coke deposition, pyrochlore materials act as a replacement to Ni other than noble metals. Pyrochlores showed significant potential towards DRM by having low coke resistance at higher temperatures. Pyrochlore materials with various effecting parameters such as substitution of transition and noble metals, modifications with promoters, alkaline earth metals and other inert supports are briefed in this review.

Numerical investigation of the reaction kinetics of dry reforming of methane over the yolk–shell and single-atom alloy catalysts

Dry reforming of methane (DRM) over Ni-based supported catalysts has been widely studied due to Ni's low cost and high activity. Despite their excellent performance, side reactions such as methane decomposition and Boudouard reaction can cause severe coke formation leading to catalyst deactivation. Our recent work reported that both yolk–shell morphology and Pt-Ni interaction in single-atom-alloy (SAA) structures could maintain the DRM activity. However, the effect of morphology and Pt-Ni interaction could not be elucidated. In this work, we studied the reaction kinetics of DRM by proposing a detailed elementary reaction mechanism with 12 surface species and 17 elementary steps over the Ptx-NiCe@SiO2 and Pt0.25-NiCe/SiO2WI catalysts. Due to the different DRM activity over the wet-impregnated and yolk–shell structures, we examined multiple reaction models to explain the effect of morphology and Pt-Ni interaction on the DRM activity. Our results show that the reverse Boudouard reaction and dissociative adsorption of CO2 and CH4 are the rate-limiting steps. The desorption of CO* and H* is also critical to products yield and selectivity. Compared with Pt0.25-NiCe/SiO2WI catalyst, the C* removal followed by the fast CO* desorption is more favored on Pt0.25-NiCe@SiO2 SAA, suggesting the reverse Boudouard reaction prevents the catalyst deactivation by coking. The high O* and low H* coverages are observed on Pt0.25-NiCe@SiO2 SAA due to the confined yolk–shell morphology and enhanced Pt-Ni interaction in SAA structures, respectively. Both these effects can lead to facile C* removal in the Pt0.25-NiCe@SiO2 SAA catalyst leading to a stable DRM activity.

Promoting Dry Reforming of Methane Catalysed by Atomically-Dispersed Ni over Ceria-Upgraded Boron Nitride.

Dry reforming of methane (DRM) is a very promising protocol to mitigate the greenhouse gases by making use of CO2 and CH4 to produce valuable syngas. Ni-based catalysts exhibit high activity and low cost for DRM, but suffer from inferior stability because of serious carbon deposition. Herein, we proposed atomically dispersed Ni supported by ceria-upgraded boron nitride whose specific activity exceeds that of boron nitride-supported Ni by 3 times. The results of temperature-programmed surface reaction show ceria enhanced the adsorption of CO2 and its surface-active oxygen species would contribute to the activation of CH4 . Moreover, Ni exhibited a strong metal-support interaction which suppressed the metal sintering during the DRM reaction while the incorporation of BN could suppress carbon deposition. The incorporation of active metal oxides into inert support provides a route to adjust the interaction between metal and support, and to achieve a synergistic improvement in catalytic performance.

Highly stable and coke-resistant Zn-modified Ni-Mg-Al hydrotalcite derived catalyst for dry reforming of methane: Synergistic effect of Ni and Zn

Considering Zinc’s basic nature and its propensity to alloy with transition metals, the improvement in the activity and carbon deposition-resistance of hydrotalcite-derived NiMgAl for the dry reforming of methane (DRM) is investigated with various Zn loadings. The prepared catalysts are characterized by various spectrometric, microscopic, and temperature-programmed techniques. Compared to the unmodified catalyst, the NiMgAl catalyst modified containing 3 wt% Zn exhibited excellent DRM activity and stability for 100 h on stream without any observable deactivation. Characterization results indicate that adding Zn to NiMgAl significantly increases the metal-support interaction, stabilizes smaller Ni particles, and minimizes carbon nanotube (CNT) growth. These advantages are a result of enhanced catalyst basicity and Ni-Zn alloy formation. Further analysis via temperature-programmed surface reaction with CH4 indicates a decrease in CH4 decomposition rate and relatively facile carbon gasification, thus increasing resistance to deactivation by coking.

Looking inside a Ni-Fe/MgAl2O4 catalyst for methane dry reforming via Mössbauer spectroscopy and in situ QXAS

The evolution of the constituents of an 8 wt%Ni-5 wt%Fe/MgAl2O4 catalyst for dry reforming of methane (DRM) is monitored by in situ quick X-ray absorption spectroscopy (QXAS) and 57Fe Mössbauer spectroscopy. In as prepared state, Fe is present as NiFe2O4 at the surface and as MgFe3+xAl2−xO4 within the support, whereas Ni is mainly present as NiO. During H2-TPR, NiFe2O4 and NiO form an alloy from 500 °C on and MgFe3+xAl2−xO4 is partially reduced to MgFe2+xAl2−xO4, such that Ni-Fe alloy, MgFe2+xAl2−xO4 and MgFe3+xAl2−xO4 are the prevalent phases in the reduced catalyst. During DRM, dominantly oxidizing environments (CH4/CO2 = 1/2, 1/1.5) lead to formation of FeOx nanoparticles at the surface of the Ni-Fe alloy, thereby affecting the DRM activity, and possibly to some reincorporation of Fe into the support. For CH4/CO2 = 1/1, no significant changes occur in the catalyst’s activated state, as a consequence of reduction by CH4 dissociation species counteracting oxidation by CO2. However, Mössbauer analysis detects continued extraction of Fe from the support, sustaining ongoing Ni-Fe alloying.

Development of Silicalite-1-encapsulated Ni nanoparticle catalyst from amorphous silica-coated Ni for dry reforming of methane: Achieving coke formation suppression and high thermal stability

Dry reforming of methane (DRM) is an important reaction for converting CO2 into synthesis gas (H2 + CO). Though Ni is one of the most promising catalysts, the agglomeration of Ni particles and the formation of coke on the catalyst proceed during DRM, resulting in rapid catalyst deactivation. Therefore, the development of Ni-based catalysts that exhibit high thermal stability and suppress coke formation is indispensable. The encapsulation structure of Ni nanoparticles in porous supports is reported to be effective for high DRM activities and the suppression of coke formation.Herein, we synthesized a Silicalite-1-encapsulated Ni catalyst (Ni@Silicalite-1) for DRM using amorphous silica-encapsulated Ni-oxide nanoparticles (NiOx@SiO2) as the Ni precursor, and the effect of physicochemical properties on DRM activities was investigated using Ni@Silicalite-1, Ni@SiO2 (NiOx@SiO2 after H2 reduction), and Ni/Silicalite-1 (impregnation). For Ni@Silicalite-1, Ni phyllosilicate was formed inside Silicalite-1 during the hydrothermal synthesis, and the encapsulation structure of 4.5-nm-sized Ni particles was realized by reducing Ni phyllosilicate to Ni particles inside the zeolite. Because the small Ni particles were stabilized in the porous supports, Ni@Silicalite-1 and Ni@SiO2 exhibited high and stable activity for DRM at 600 °C with negligible coke formation (6.6 and 8.2 mg-C/g-catalyst for Ni@Silicalite-1 and Ni@SiO2 respectively), whereas a large amount of coke was formed on Ni/Silicalite-1 (532 mg-C/g-catalyst). Ni@Silicalite-1 exhibited high and stable DRM activity throughout 24 h at 600 °C and GHSV = 108000 mL/(g-cat·h). Moreover, because Silicalite1 possessed high thermal stability, the high activity of Ni@Silicalite-1 was maintained throughout the 5 h of DRM at 850 °C, whereas the activity of Ni@SiO2 decreased because of the collapse of the pore structure of SiO2. Ni@Silicalite1 exhibited a higher conversion rate of methane (13.3 mol-CH4/(g-Ni·min) at 850 °C and GHSV = 1080000 mL/(g-cat·h)) than previously reported Ni-based catalysts.

Exsolution of Ni Nanoparticles from A-Site-Deficient Layered Double Perovskites for Dry Reforming of Methane and as an Anode Material for a Solid Oxide Fuel Cell.

Exsolution is a promising technique to design metal nanoparticles for electrocatalysis and renewable energy. In this work, Ni-doped perovskites, (Pr0.5Ba0.5)1-x/2Mn1-x/2Nix/2O3-δ with x = 0, 0.05, 0.1, and 0.2 (S-PBMNx), were prepared to design exsolution systems as solid oxide fuel cell anodes and for catalysis applications. X-ray diffraction and transmission electron microscopy (TEM) analyses demonstrated that correlating A-site deficiency with Ni content can effectively induce exsolution of all Ni under H2 atmosphere at T ∼ 875 °C, yielding the reduced (exsolved) R-PBMNx materials. On heating the exsolution systems in air, metal incorporation in the oxide lattice did not occur; instead, the Ni nanoparticles oxidized to NiO on the layered perovskite surface. The lowest area-specific resistance (ASR) under wet 5% H2/N2 in symmetrical cells was observed for R-PBMN0.2 anode (ASR ∼ 0.64 Ω cm2 at 850 °C) due to the highest Ni particle density in the R-PBMNx series. The best performance for dry reforming of methane (DRM) was also obtained for R-PBMN0.2, with CH4 and CO2 conversion rates at 11 and 32%, respectively, and the highest production of H2 (37%). The DRM activity of R-PBMN0.2 starts at 800 °C and is sustained for up to at least 5 h operation with little carbon deposition (0.017 g·gcat-1·h-1). These results clearly demonstrate that varying Ni-doping in layered double perovskite oxides is an effective strategy to manipulate the electrochemical performance and catalytic activity for energy conversion purposes.

Promotion of Hydrogen Oxidation and Methane Dry Reforming Over Ni-SDC Anode by Basic Oxide Additives

Promoting effects of the additives such as MgO, CaO, BaO, and Cr2O3 to Ni-SDC (samarium-doped ceria) anodes were investigated on hydrogen oxidation and dry reforming of methane (DRM) activity. The additives were found to elevate current-voltage characteristics of H2-O2 fuel cells. The polarization resistance for H2 oxidation at the anodes was mainly decreased by the additives. The carbon balance in DRM reaction at open circuit voltage (OCV) approached 100% over the modified Ni-SDC anodes. The DRM activity was most promoted by the Cr2O3 additive, leading the highest OCV in direct DRM operation.

Efficient integration of CO2 capture and conversion over a Ni supported CeO2-modified CaO microsphere at moderate temperature

Efficient integration of calcium-looping (CaL) and dry reforming of methane (DRM), termed as CaLDRM, into an isothermal process implemented on a bifunctional Ni-CaO based material is a promising technology to achieve CO2 capture and in-situ conversion to syngas, thereby allowing a win–win for environment and economy. The core of this technology is the employed material which should ensure both good CO2 capture capacity and significant catalytic activity at a temperature matching CaL and DRM. To this end, we synthesize a Ni supported porous CeO2-modified CaO microsphere to serve as the bifunctional material by a combination of template-assisted hydrothermal and impregnation method. This material successfully drives cyclic CO2 capture and conversion at the same temperature of 650 °C, i.e. simultaneously realizing high-temperature CaL and low-temperature DRM. The role of Ce on boosting the material performance originates from two aspects: on the one hand, the homogeneously mixed CeO2, as an activity promoter, enhances the CO2 affinity of CaO and the low-temperature activity of Ni, enabling higher CO2 capture and conversion capacities at 650 °C; on the other hand, it, as a structure stabilizer, improves the sinter resistance of CaO and the dispersion of Ni, maintaining the CaL kinetics and catalytic DRM activity. Following the premise of minimizing additive quantity, the bifunctional material constructed from the support with a Ca:Ce molar ratio of 85:15 shows stable CO2 uptake and syngas yield during the isothermal CaLDRM cycles at 650 °C, exceeding the performance of unmodified material by more than 2 times.

Evaluation of NiO/TALC Catalytic performance in carbon dioxide reforming of methane

A series of NiO/Talc (Talc = talcum) catalysts with various Ni loadings (5–15 wt%) has been synthesised via the wet impregnation method and utilised for dry reforming of methane (DRM). All catalysts showed promising catalytic DRM performance and 10%NiO/Talc was found to be the most effective catalyst with 98% CH4 and 80% CO2 conversion respectively (SH2 = 65%; H2/CO close to ⁓1.2) at 700 °C reaction temperature under 1 atm pressure reaction condition. This finding confirmed that excellent DRM activity was corroborated with the high surface area, good NiO dispersion, good basic properties, excellent reducibility and formation of the Mg2Ni phase. The DRM increased with reaction temperature, whereas 700 to 800 °C showed the most optimum activity. The 10%NiO/Talc catalyst appears to have longer a lifetime (highly stable) with low coke affinity. This is confirmed by the high and consistent (CH4 & CO2) conversion with moderate carbon formation (20 wt%) over 10 h reaction time.

Strong impact of indium promoter on Ni/Al2O3 and Ni/CeO2-Al2O3 catalysts used in dry reforming of methane

Herein, the promotion effect of only 0.3 wt% indium on 3% Ni/Al2O3 and 3% Ni/CeO2-Al2O3 catalysts prepared by deposition-precipitation over a commercial alumina and on the CeO2-modified support was studied. Catalyst characterization by XRD, TPR, XPS, TEM, CO-DRIFTS was performed. The catalytic properties were investigated and coke formation was analyzed under temperature ramped CH4-decomposition and in Dry Reforming of Methane (DRM). The unique impact of indium was compared to the well-known effects of ceria additive. The carbon deposition on Ni/Al2O3 blocking the reactor could be only delayed due to ceria on Ni/CeO2-Al2O3, while NiIn/Al2O3 was able to maintain the activity in DRM. Indium modifier acting in parallel with ceria over NiIn/CeO2-Al2O3 determined the least coking, but the least catalytic activity. The results were discussed in terms of double role of In, acting as a ceria modifier, upgrading its oxidative properties and as a metal modifier, getting alloyed with Ni.

Synthesis of Highly-Dispersed Ni/Mesoporous Silica via an Ammonia Evaporation Method for Dry Reforming of Methane: Effect of the Ni Loadings

Mesoporous silica was used in conjunction with the ammonia evaporation method to prepare highly dispersed Ni catalysts for the dry reforming of methane (DRM). The effect of Ni dispersion on the catalytic performance was investigated by applying different Ni loadings. The pore structure, morphology, Ni dispersion, catalytic activity for DRM as well as the coke resistance were investigated. During the reaction at a relatively low temperature of 600 °C, all the three catalysts exhibited high stability in CH4 and CO2 conversion and excellent coke resistance, in comparison to Ni/SiO2 catalyst prepared by the incipient wetness method. Among them, 10% Ni–SiO2 exhibited the best catalytic performance with the maximum steady conversions of 62% and 69% for CH4 and CO2 at 600 °C, which was beneficial from its optimal Ni content and the presence of highly-dispersed metal nanoparticles confined in the mesopores.

Single-Step Flame Aerosol Synthesis of Active and Stable Nanocatalysts for the Dry Reforming of Methane.

We introduce a flame-based aerosol process for producing supported non-noble metal nanocatalysts from inexpensive aqueous metal salt solutions, using catalysts for the dry reforming of methane (DRM) as a prototype. A flame-synthesized nickel-doped magnesia (MgO) nanocatalyst (NiMgO-F) was fully physicochemically characterized and tested in a flow reactor system, where it showed stable DRM activity from 500 to 800 °C. A kinetic study was conducted, and apparent activation energies were extracted for the temperature range of 500-650 °C. It was then compared with a Ni-decorated MgO nanopowder prepared by wet impregnation of (1) flame-synthesized MgO (NiMgO-FI) and (2) a commercial MgO nanopowder (NiMgO-CI) and with (3) a NiMgO catalyst prepared by co-precipitation (NiMgO-CP). NiMgO-F showed the highest catalytic activity per mass and per metallic surface area and was stable for continuous H2 production at 700 °C for 50 h. Incorporation of potential promoters and co-catalysts was also demonstrated, but none showed significant performance improvement. More broadly, nanomaterials produced by this approach could be used as binary or multicomponent catalysts for numerous catalytic processes.

Dry reforming of methane over Ni–ZrOx catalysts doped by manganese: On the effect of the stability of the structure during time on stream

Ni–Mn–ZrOx catalyst prepared by a one-step urea hydrolysis method was tested in the dry reforming of methane (DRM) reaction at medium temperature. The catalyst was characterized by H2-TPR, CO2-TPD, XRD, XPS, TGA, Raman, and TEM. On Ni–Mn–ZrOx catalyst, the catalytic activity increased with time on stream, while a decrease was observed on Ni–ZrOx catalyst. In order to understand this phenomenon, the catalysts were characterized at pre-reaction and during reaction for different time on stream such as 100 min, 300 min, and 480 min. According to the XPS results, it was shown that the Zr species on Ni–ZrOx were reduced during the reaction, whereas the Zr species was almost in equilibrium on Ni–Mn–ZrOx catalyst. In combining the results of XRD and activity in DRM, we can conclude that a stable ZrO2 structure on Ni–Mn–ZrOx catalyst might promote the redox of nickel species during the reaction, and further promote the redistribution of nickel species. However, on the Ni-ZrOx catalyst, the unstable ZrO2 support might result in a decrease of surface nickel content while an increase of Ni particle size, thus led to a decrease of activity for DRM.