Enhance the activity of multi-carbon products for Cu via P doping towards CO₂ reduction

Abstract

Electronic structure engineering is a powerful method to tailor the behavior of adsorbed intermediates on the surface of catalysts, thus regulating catalytic activity towards CO₂ electroreduction. Herein, we prepared a series of P-doped Cu catalysts for CO₂ electroreduction into multi-carbon (C₂₊) products by regulating the surface electronic structure of Cu. The introduction of P could stabilize the surface Cu^δ+ species, enhancing the activity for C₂₊ products via adjusting the adsorbed strength of the CO intermediates (*CO). When the molar ratio of P to Cu was 8.3%, the catalyst exhibited a Faradaic efficiency of 64% for C₂₊ products, which was 1.9 times as high as that (33%) for Cu catalysts at the applied current density of 210 mA cm⁻². Notably, at the applied current density of 300 mA cm⁻², the P-doped Cu catalyst with the molar ratio of P to Cu of 8.3% exhibited the highest partial current density for C₂₊ products of 176 mA cm⁻², whereas the partial current density for C₂₊ products over the Cu catalyst was only 84 mA cm⁻². Mechanistic studies revealed that modulating the molar ratios of P to Cu regulated the adsorbed strength of *CO. A moderate adsorbed strength of *CO induced by appropriate P doping was responsible for the facilitated C-C coupling process.