Phosphorus-Mediated Oxygen Vacancy Engineering in Cu₂O for Highly Selective CO₂ Electroreduction to Multicarbon Products.

Abstract

Copper (Cu)-based electrocatalysts are acknowledged as pivotal catalysts for the electroreduction of CO₂ into multicarbon (C₂₊) products; however, achieving high C₂₊ selectivity at industrial-level current densities remains a significant challenge. Herein, we propose a "phosphorus (P)-doping mediation" strategy to introduce an oxygen vacancy into the Cu₂O lattice, resulting in a C₂₊ Faradaic efficiency of 87.0% at a partial current density of 347.8 mA·cm^-2. Mechanistic studies unveil that P dopants dynamically regulate the formation of high-density oxygen vacancies in Cu₂O lattices through the formation and subsequent detachment of the P-O bond, predominantly in the form of phosphite within an aqueous electrolyte environment. <i>In situ</i> Raman spectroscopy coupled with density functional theory calculations further reveals that the OV-rich structure optimizes the surface coverage of active *CO intermediates. This microenvironment not only accelerates the energetically favorable C-C coupling pathway but also suppresses competitive protonation reactions, thereby breaking the intrinsic activity-selectivity trade-off. Our work provides atomic-level insights into defect dynamics manipulation for designing high-rate CO₂ conversion systems.