Surface modification and reconstruction of ZnO hollow microspheres for selective electroreduction of CO2 to CO

Abstract

Surface chemistry can be modified by introducing another component on the surface of catalyst due to the regulation of configuration and electronic properties. Herein, the nanostructured ZnO hollow microspheres were fabricated for selective CO2 reduction to CO. The addition of CuO weakens the strength of adjacent Zn-O bond and improves the formation of more zero-valence Zn. Small CuO entities can provide the active sites for CO2 adsorption, and the presence of surface defects due to Zn2+ reduction could enhance initial dissociation from CO2 to CO. More interestingly, the 3CuO/ZnO catalyst underwent reconstruction during electrocatalysis, and multi-shelled hollow spheres evolved into a thin flaky structure. The extended surface area of flaky morphology enhances the catalytic stability despite the occurrence of ZnO reduction. This study highlights the importance of surface modification for CO2 selective reduction to CO but also provides some insights on reconstruction during electrochemical reduction of CO2.