S-dopant and O-vacancy of mesoporous ZnO nanosheets induce high efficiency and selectivity of electrocatalytic CO2 reduction to CO

Abstract

Surface engineering can adjust the electronic properties of catalysts, thereby boosting their electrocatalytic performances. Herein, S-doped and O-vacant mesoporous ZnO nanosheets (ZnO-VO-S) were synthesized through the plasma-treatment method, exhibiting highly electrocatalytic selectivity and activity in the conversion of CO2 to CO. Synchrotron X-ray absorption fine structure (XAFS) investigations were used to further clarify the valence state and local coordination structure of Zn, concretely affirming the reduced electron density of Zn in ZnO-VO-S. Specifically, at −1.1 V vs. RHE, the as-prepared ZnO-VO-S demonstrated a high Faradaic efficiency of 90%. Experiments and density functional theory (DFT) suggest that the electron deficiency of Zn caused by the introduction of S dopant and O vacancy, reduces the energy barrier of CO2 to CO by improving the adsorption behavior of the intermediate *COOH.