Reaction Mechanism and Catalytic Impact of Ni/CeO2–x Catalyst for Low-Temperature CO2 Methanation

Ni supported on calcined ceria nitrate catalyst is highly active and stable for low-temperature CO 2 methanation reaction (CO 2 conversion: 70% at 180 °C, 0.05 bar, and gas hourly space velocity (GHSV) of 14 400 L kg –1 h –1 ). We investigated CO 2 adsorption and CO 2 + H 2 reaction on the surface of Ni/CeO 2 and Ni/CeO 2– x catalysts to examine the structure and strength of adsorbed species using diffuse reflection infrared Fourier transform spectroscopy (DRIFTS). At temperature of 180 °C, weakly adsorbed bridged carbonate was generated on the surface of CeO 2– x support by new active sites of oxygen vacancies created by addition of H 2 . High reducibility of Ni/CeO 2– x catalyst played an important role in increasing low-temperature CO 2 methanation catalytic activity.