Optimizing Copper Oxidation State to Promote Ethylene Generation in Efficient Carbon Dioxide Conversion

The electrochemical reduction of carbon dioxide (CO2) to valuablecarbon-based fuels and chemicals has attracted extensive attention. In this work, different copper catalysts have been prepared to explore the roles of different oxidationstates on the activity and selectivity of CO2reduction. The optimal oxidation state ofcopper catalyst provides 53% Faradaic efficiency (FE) for converting CO2to ethyleneand achieves a maximum FE of 74% for C2 hydrocarbons (ethylene and ethanol) at-1.3 V vs reversible hydrogen electrode (RHE). Moreover, characterization andelectrochemical results show that with the decrease of oxidation state of coppercatalysts, methane is mainly inhibited, while ethylene dominates in a wide potentialwindow. This work provides reliable experimental evidence and valuable insights in adjusting the oxidation state of copper catalysts to achieve high selectivity of hydrocarbon products, which may provide important guidance for the design and preparation of efficient catalysts for selective CO2electroreduction to valuable products