CO 2 Activation on Cobalt Surface in the Presence of H 2 O: An Ambient-Pressure X-ray Photoelectron Spectroscopy Study

Co-based catalysts for CO 2 reduction to liquid fuels have been attracting increasing attention. In this work, the distribution of surface intermediates on a polycrystalline Co foil was investigated by ambient-pressure X-ray photoelectron spectroscopy (APXPS) experiments under near ambient pressure and temperature conditions. The Co surface was partially oxidized, predominantly by carbonates, after CO 2 dissociative adsorption. Graphitic carbon deposition on the partially oxidized Co surface was significantly lesser than that on the open surfaces of Cu and Ni under similar reaction conditions. Methoxy, formate, and a bulk carbonate formed upon the co-adsorption of H 2 O with a surprisingly high methoxy/formate coverage ratio. These results provide valuable mechanistic information for developing highly selective Co-based catalysts for CO 2 reduction. Graphical Abstract