Electrocatalytic CO2-to-C2+ with Ampere-Level Current on Heteroatom-Engineered Copper via Tuning *CO Intermediate Coverage

An ampere-level current density of CO2 electrolysis is critical to realize the industrial production of multicarbon (C2+) fuels. However, under such a large current density, the poor CO intermediate (*CO) coverage on the catalyst surface induces the competitive hydrogen evolution reaction, which hinders CO2 reduction reaction (CO2RR). Herein, we report reliable ampere-level CO2-to-C2+ electrolysis by heteroatom engineering on Cu catalysts. The Cu-based compounds with heteroatom (N, P, S, O) are electrochemically reduced to heteroatom-derived Cu with significant structural reconstruction under CO2RR conditions. It is found that N-engineered Cu (N-Cu) catalyst exhibits the best CO2-to-C2+ productivity with a remarkable Faradaic efficiency of 73.7% under -1100 mA cm-2 and an energy efficiency of 37.2% under -900 mA cm-2. Particularly, it achieves a C2+ partial current density of -909 mA cm-2 at -1.15 V versus reversible hydrogen electrode, which outperforms most reported Cu-based catalysts. In situ spectroscopy indicates that heteroatom engineering adjusts *CO adsorption on Cu surface and alters the local H proton consumption in solution. Density functional theory studies confirm that the high adsorption strength of *CO on N-Cu results from the depressed HER and promoted *CO adsorption on both bridge and atop sites of Cu, which greatly reduces the energy barrier for C-C coupling.