Modulating surface zinc species via facet engineering for efficient electroreduction of CO2 to CO

Abstract

Zn-based catalysts have attracted widespread interest in electrocatalytic reduction of CO2 to CO, but they struggle to achieve large current densities and high product selectivity. Herein, we develop two kinds of faceted ZnO nanorods with subtle changes in crystallography and surface composition, simply by adjusting thermal annealing conditions. The ZnO nanorods with high numbers of (101) facets (ZnO (101)) and a reorganized Zn-rich surface exhibit higher catalytic performance compared to conventional ZnO nanorods with more (002) crystal planes and an oxygen-rich surface. The ZnO (101) catalyst shows superior FECO (>90 %) over a broad potential range, and an attractive CO partial current density of − 215.3 mA cm−2 in flow cells. DFT results further reveal that CO2 molecules are more easily activated on the reorganized surface of the ZnO (101), which significantly facilitates the formation of *COOH and inhibits the hydrogen evolution reaction, leading to remarkable activity and selectivity.