Effect of CeO2 addition on Ni/Al2O3 catalysts for methanation of carbon dioxide with hydrogen

Abstract

The Ni-CeO₂/Al₂O₃ catalysts with a nickel content of 15 wt% prepared via impregnating boehmite were found to be highly active and stable for methanation of carbon dioxide with hydrogen at a H₂/CO₂ molar ratio of 4. The effects of CeO₂ content and reaction temperature on the performance of the Ni-CeO₂/Al₂O₃ catalysts were studied in detail. The results showed that the catalytic performance was strongly dependent on the CeO₂ content in Ni-CeO₂/Al₂O₃ catalysts and that the catalysts with 2 wt% CeO₂ had the highest catalytic activity among the tested ones at 350 °C. The XRD and H₂-TPR characterizations revealed that the addition of CeO₂ decreased the reduction temperature by altering the interaction between Ni and Al₂O₃, and improved the reducibility of the catalyst. Preliminary stability test of 120 h on stream over the Ni-2CeO₂/Al₂O₃ catalyst at 350 °C revealed that the catalyst was much better than the unpromoted one.