Effect of support calcination temperature on the catalytic properties of Ru/Ce_0.8Zr_0.2O₂ for methanation of carbon dioxide

A series of Ru/Ce_0.8Zr_0.2O₂ catalysts were prepared by the impregnation method with Ce_0.8Zr_0.2O₂ homoprecipitated and calcined at different temperatures as supports. The supports and the catalysts were characterized with TG-DSC, BET and H₂-TPR techniques. It was shown that the Ce_0.8Zr_0.2O₂ calcined at 500 ℃ formed Ce-Zr solid solution and had a proper surface area and pore opening and a weak interaction with Ru species, leading to a significant increase in the catalytic activity. A suitable reduction methods promoted distribution of active species. The Ru/Ce_0.8Zr_0.2O₂ prepared with the Ce_0.8Zr_0.2O₂ calcined at 500 ℃ showed high activity after calcination at 400 ℃ and successive reduction with H₂N·NH₂·H₂O and H₂. It gave a H₂ conversion of 93.57%, approaching to the equilibrium value under the conditions of 290 ℃, 0.1 MPa, 10 000 h^-1 and H₂/CO₂ mol ratio of 3.5.