Ni/CeO_2 catalysts with high CO_2 methanation activity and high CH_4 selectivity at low temperatures

摘要

CO_2 methanation was performed over 10 wt%Ni/CeO_2, 10 wt%Ni/α-Al_2O_3, 10 wt%Ni/TiO_2, and 10 wt%Ni/MgO, and the effect of support materials on CO_2 conversion and CH_4 selectivity was examined. Catalysts were prepared by a wet impregnation method, and characterized by BET, XRD, H2-TPR and CO_2-TPD. Ni/CeO_2 showed high CO_2 conversion especially at low temperatures compared to Ni/a-Al_2O_3, and the selectivity to CH4 was very close to 1. The surface coverage by CO_2-derived species on CeO_2 surface and the partial reduction of CeO_2 surface could result in the high CO_2 conversion over Ni/CeO_2. In addition, superior CO methanation activity over Ni/CeO_2 led to the high CH_4 selectivity.