▎ 摘　　要

The electrochemical reduction of CO2 has been recognized as one of the best strategies to reduce atmospheric CO2 levels and achieve a carbon-neutral economy. We report here a copper complex, Cu(salan)(2), as an efficient CO2 reduction catalyst in basic aqueous media. Cu(salan)(2) exhibited different catalytic behaviors in nanocrystalline and graphene-supported forms. As nanocrystals, the complex did not show high catalytic activity and gradually decomposed into Cu2O upon electrolysis. However, when dispersed on a graphene matrix, Cu(salan)(2) exhibited a moderate-to-high CO selectivity and remained stable in long-term electrolysis. This work shows that site-isolation by dispersion of a molecular catalyst is an effective way to increase the catalyst stability and tune the product selectivity for CO2RR electrocatalysis.