Efficient Electroreduction of CO2 to CH4 on Ultrasmall Copper Nanoparticles

Electroreduction of carbon dioxide (CO2) into valuable chemicals and fuels is a promising strategy to mitigate energy and environmental problems. However, the poor selectivity and inadequate electrochemical stability prevent practical applications. In this work, we prepared ultrasmall copper (Cu) nanoparticles by using tannic acid as a complexing agent and stablizer. The ultrasmall Cu nanoparticles (3.4 nm) exhibited outstanding performance for CO2 electroreduction to CH4. The Faradaic efficiency of CH4 could reach up to 68% at - 1.2 V versus reversible hydrogen electrode (RHE), with high current density of 475 mA <middle dot> cm-2. The ultrasmall Cu nanoparticles could enhance the CO adsorption and H2O activation, resulting in the high selectivity of CH4.