Computational Design of a Two-Dimensional Copper Carbide Monolayer as a Highly Efficient Catalyst for Carbon Monoxide Electroreduction to Ethanol.

Rationally designing stable and low-cost electrocatalysts with high efficiency is of great significance for the large-scale electrochemical reduction of carbon monoxide (eCOR) to high-value-added multicarbon products. Inspired by the tunable atomic structures, abundant active sites, and excellent properties of two-dimensional (2D) materials, in this work, we designed several novel 2D C-rich copper carbide materials as eCOR electrocatalysts by performing an extensive structural search and comprehensive first-principles computations. According to the computed phonon spectra, formation energies, and ab initio molecular dynamics simulations, we screened out two highly stable candidates, i.e., CuC2 and CuC5 monolayers with metallic features. Interestingly, the predicted 2D CuC5 monolayer exhibits superior eCOR performance for C2H5OH synthesis with high catalytic activity (low limiting potential of -0.29 V and small activation energy for C-C coupling of 0.35 eV) and high selectivity (significant suppressing effect on the side reactions). Thus, we predicted that the CuC5 monolayer holds great potential as an eligible electrocatalyst for CO conversion to multicarbon products, which could motivate more study to develop highly efficient electrocatalysts in similar binary noble-metal compounds.