Methanation of Carbon Dioxide over Ni-Ce-Zr Oxides Prepared by One-Pot Hydrolysis of Metal Nitrates with Ammonium Carbonate

Ni-Ce-Zr mixed oxides were prepared through one-pot hydrolysis of mixed metal nitrates with ammonium carbonate for CO2 methanation. The effects of Ce/Zr molar ratio and Ni content on catalysts' physical and chemical properties, reduction degree of Ni2+, and catalytic properties were systematically investigated. The results showed that Zr could lower metallic Ni particle sizes and alter interaction between Ni and supports, resulting in enhancements in the catalytic activity for CO2 methanation. The Ni-Ce-Zr catalyst containing 40 wt % Ni and Ce/Zr molar ratio of 9:1 exhibited the optimal catalytic properties, with 96.2% CO2 conversion and almost 100% CH4 selectivity at a low temperature of 275 degrees C. During the tested period of 500 h, CO2 conversion and CH4 selectivity over Ni-Ce-Zr catalyst kept constant under 300 degrees C.