Effect of Ce/Zr composition and noble metal promotion on nickel based CexZr1−xO2 catalysts for carbon dioxide methanation

• Published in: Applied catalysis. A, General Vol. 392; no. 1-2; pp. 36 - 44
• Main Authors: Ocampo, Fabien, Louis, Benoit, Kiwi-Minsker, Lioubov, Roger, Anne-Cécile
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 29.01.2011; Elsevier
• Subjects: Carbon dioxide; Catalysis; Ceria–zirconia; Chemistry; Colloidal gels. Colloidal sols; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Methanation; Mixed oxides; Synthetic fuels; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Ceria–zirconia; Synthetic fuels; Methanation; Mixed oxides; Carbon dioxide; Methane; Modification; Binary compound; Incorporation; Support; Doping; Selectivity; Cerium oxide; Lanthanide compound; Specific activity; Zirconium oxide; Ceria-zirconia; Noble metal; Structure; Scanning electron microscopy; Composition; Catalytic reaction; Transition element compounds; Transition metal; Conversion; X ray diffraction; Zirconia; Heterogeneous catalysis; Sol gel process; Fuel; Nickel; Catalyst activity; Catalyst
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2010.10.025

[Display omitted] ▶ 5wt% Ni based CexZr1−xO2 with C/Z mass ratios ranging from 4 to 0.25 and Ru or Rh promoted Ce0.72Zr0.28O2 catalysts were successfully synthesized. ▶ C/Z and noble metal addition effects were evaluated on catalyst structural properties and catalytic activity in CO2 methanation reaction. ▶ Impressive CO2 conversion and extremely high selectivity to methane (superior to 98%). ▶ Both incorporated Ni2+/Ni0 ratio optimization and noble metal addition boosted the catalyst performance. ▶ 5Ni(60–40) appeared to be the best catalytic system. Carbon dioxide methanation was carried out over a series of Ni–CexZr1−xO2 catalysts prepared by a pseudo sol–gel method. The influence of CeO2/ZrO2 mass ratio and noble metal addition was investigated. The catalysts were subsequently characterized by means of XRD, TPR, BET, H2-TPD and SEM-EDX. The modification of structural and redox properties of these materials was evaluated in relation with their catalytic performances. All catalysts gave impressive CO2 conversion and extremely high selectivity to methane (superior to 98%). Ni2+ incorporation into the CZ structure was proved to enhance catalysts specific activity. The global performance of the studied systems depended not only on the surface of available metallic nickel but also on the composition of the support and on its modification by Ni2+ doping. As a result of these two phenomena, the Ni-based mixed oxide having a CeO2/ZrO2=60/40 exhibited the highest catalytic activity, owing to an optimal Ni2+/Ni0 ratio. Noble metal addition led to higher Ni dispersion, resulting in a raise of both activity and catalyst life-time. It did not modify the support intrinsic activity. The deactivation was shown not to be due to carbon deposits but rather to nickel particles sintering. The investigated parameters thus allowed an improvement of the previously studied 5wt% Ni–Ce0.72Zr0.28O2 system.