SnO₂-Modified Two-Dimensional CuO for Enhanced Electrochemical Reduction of CO₂ to C₂H₄

Electrochemical reduction of CO2 was a widespread method for CO2 conversion into valuable chemical fuel. C2H4 is an important product from CO2 reduction. However, conversion of CO2 into the hydrocarbon C2H4 faced large energy barriers. Herein, we, for the first time, achieve a high efficiency for electrochemical conversion of CO2 to C2H4 on a tin-modified CuO. By modifying with Sn, we obtained a related low onset potential of C2H4 as positive as −0.8 V versus RHE and a high Faradaic efficiency of C2H4 as high as 22% at −1.0 V (vs RHE). According to density functional calculation, the Sn dopant mainly enriched the electron density of CuO, while it was electron-poor in the Sn dopants. The rate of CO2 reduction can be enhanced on Cu nanosheets with higher electron density. We believed that this work would promote the development of two-dimensional catalysts for CO2 conversion and deepen the understanding of doping on CO2 reduction.