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

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, Cu3P@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, Cu2Se@C and Cu1.8S@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 Cu3P on the electronic properties of carbon binding sites and the underlying mechanisms for methanol production.