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 · cm⁻². The ultrasmall Cu nanoparticles could enhance the CO adsorption and H₂O activation, resulting in the high selectivity of CH₄. Formula Presented.