Highly Efficient Electroreduction of CO₂ to C2+ Alcohols on Heterogeneous Dual Active Sites

Abstract

Electroreduction of CO₂ to liquid fuels such as ethanol and n-propanol, powered by renewable electricity, offers a promising strategy for controlling the global carbon balance and addressing the need for the storage of intermittent renewable energy. In this work, we discovered that the composite composed of nitrogen-doped graphene quantum dots (NGQ) on CuO-derived Cu nanorods (NGQ/Cu-nr) was an outstanding electrocatalyst for the reduction of CO₂ to ethanol and n-propanol. The Faradaic efficiency (FE) of C2+ alcohols could reach 52.4 % with a total current density of 282.1 mA cm^-2 . This is the highest FE for C2+ alcohols with a commercial current density to date. Control experiments and DFT studies show that the NGQ/Cu-nr could provide dual catalytic active sites and could stabilize the CH₂ CHO intermediate to enhance the FE of alcohols significantly through further carbon protonation. The NGQ and Cu-nr had excellent synergistic effects for accelerating the reduction of CO₂ to alcohols.