Modulating Electronic Properties of Carbon for Selective Electrochemical Reduction of CO₂ to Methanol on Cu₃P@C

Abstract

Carbon layer-coated CuX (CuX@C, X = P, S, Se) with different electron densities on the carbon coating layers have been successfully prepared. Among them, Cu 3 P@C, which has a high-electron-density carbon coating layer, delivers a high faradaic efficiency for methanol of 61.2% at −0.36 V versus reversible hydrogen electrode (RHE), and a record partial current density for methanol of 130 mA cm –2 at −0.76 V versus RHE when it is assembled on a gas diffusion electrode in a flow cell setup using 1 M KOH electrolyte, outperforming most of the state-of-the-art electrocatalysts. In contrast, Cu 2 Se@C and Cu 1.8 S@C, which have low-electron-density carbon coating layers, predominately produce formate. In situ Raman spectroscopy analysis and computational density functional theory calculations reveal the influence of Cu 3 P on the electronic properties of carbon binding sites and the underlying mechanisms for methanol production.