Abstract
The selectivity and activity of a nickel catalyst for the hydrogenation of carbon dioxide to form methane at low temperatures could be enhanced by mesoporous Al(2)O(3)-CeO(2) synthesized through a one-pot sol-gel method. The performances of the as-prepared Ni/Al(2)O(3)-CeO(2) catalysts exceeded those of their single Al(2)O(3) counterpart giving a conversion of 78% carbon dioxide with 100% selectivity for methane during 100 h testing, without any deactivation, at the low temperature of 320 °C. The influence of CeO(2) doping on the structure of the catalysts, the interactions between the mesoporous support and nickel species, and the reduction behaviors of Ni(2+) ions were investigated in detail. In this work, the addition of CeO(2) to the composites increased the oxygen vacancies and active metallic nickel sites, and also decreased the size of the nickel particles, thus improving the low temperature catalytic activity and selectivity significantly.