A metallic Cu2N monolayer with planar tetracoordinated nitrogen as a promising catalyst for CO2 electroreduction

The electrochemical carbon dioxide reduction reaction (CO2RR) holds great promise for mitigating CO2 emission and simultaneously generating high energy fuel. However, it remains a great challenge to reduce CO2 to C-2 products due to the lack of highly efficient catalysts. Herein, by means of a particle swarm optimization search and comprehensive density functional theory (DFT) computations, we predicted a hitherto unknown Cu2N monolayer with planar hexacoordinate Cu and tetracoordinate N atoms as a CO2RR catalyst. Our results revealed that the Cu2N monolayer shows outstanding stability and intrinsic metallicity. Interestingly, the as-designed Cu2N monolayer exhibits superior CO2RR catalytic performance with a rather low limiting potential (-0.33 V), resulting in the formation of a C2H4 product with a small kinetic barrier (0.55 eV) for the coupling between *CH2 and a CO molecule. Strikingly, the N atoms within the Cu2N monolayer were revealed to be the CO2RR active sites due to their significant binding strength with the CO2RR species and their significant spin moments. Our findings not only propose a useful roadmap for the discovery of 2D hypercoordinate materials, but also provide cost-effective opportunities for advancing sustainable CO2 conversion.

Automated summary

Research predicted a previously unknown Cu2N monolayer as a highly efficient catalyst for CO2RR through particle swarm optimization search and comprehensive density functional theory computations, showing outstanding stability, intrinsic metallicity, and superior catalytic performance.