Hybrid Cu0 and Cux+ as Atomic Interfaces Promote High-Selectivity Conversion of CO2 to C2H5OH at Low Potential

The mixing of charge states of metal copper catalysts may lead to a much improved reactivity and selectivity toward multicarbon products for CO2 reduction. Here, an electrocatalyst model composed of copper clusters supported on graphitic carbon nitride (g-C3N4) is proposed; the connecting Cu atoms with g-C3N4 can be oxidized to Cu-x (+) due to substantial charge transfer from Cu to N atoms, while others stay as Cu-0. It is revealed that CO2 can be captured and reduced into *CO on the Cu-t(0) site, owing to its zero oxidation state. More importantly, C-C coupling reaction of two *CHO species on the Cu-t(0)-Cu-b(x) (+) atomic interface can occur with a rather low kinetic barrier of 0.57 eV, leading to the formation of the final C-2 product, namely, C2H5OH. During the whole process, the limiting potential is just 0.68 V. These findings may open a new avenue for CO2 reduction into high-value fuels and chemicals.