Catalytic Conversion of Carbon Dioxide to Methane on Ruthenium-Cobalt Bimetallic Nanocatalysts and Correlation between Surface Chemistry of Catalysts under Reaction Conditions and Catalytic Performances

Catalytic conversion of CO2 to CH4 on-cobalt oxide and Ru-doped cobalt oxide nanorods was studied with in-house ambient pressure X-ray photoelectron spectroscopy (AP-XPS) using monochromated Al K alpha. A correlation between catalytic performances of the two catalysts and their surface chemistry under reaction conditions was built. Active phases of the two catalysts are metallic cobalt and bimetallic Co-Ru, respectively. Light-off temperature of Co-Ru catalyst is lower than that of a cobalt catalyst. Selectivity to production of CH4 and activity on the Ru-doped cobalt oxide are obviously enhanced by formation of bimetallic Co-Ru ultrathin film in its surface region in contrast to that of cobalt catalyst in the temperature range of 200-340 degrees C.