Additives‐Modified Electrodeposition for Synthesis of Hydrophobic Cu/Cu2O with Ag Single Atoms to Drive CO2 Electroreduction

Abstract Copper‐based electrocatalysts are recognized as crucial catalysts for CO 2 electroreduction into multi‐carbon products. However, achieving copper‐based electrocatalysts with adjustable valences via one‐step facile synthesis remains a challenge. In this study, Cu/Cu 2 O heterostructure is constructed by adjusting the anion species of the Cu ions‐containing electrolyte during electrodeposition synthesis. Then, Cu/Cu 2 O with tuned nanoarchitectures ranging from dendrites to polyhedrons is achieved by introducing transition metal ions as additives, leading to an adjustable interfacial microenvironment for CO 2 /H 2 O adsorption on the Cu/Cu 2 O electrodes. Additionally, the polyhedral Cu/Cu 2 O catalysts are used as templates for depositing Ag single atoms (Ag SA ), which are known as synergistic active sites for promoting * CO to * COH toward C 2+ products. The prepared Ag SA ‐Cu/Cu 2 O catalyst is evaluated in a flow cell and exhibited a FE C2+ of 90.2% and a partial current density (jc 2+ ) of 426.6 mA cm −2 for CO 2 electroreduction. As revealed by in situ Raman spectra and density functional theory calculations, the introduction of Ag single atoms slows down the reduction of Cu + during CO 2 electroreduction, especially at a high current density. This work provides a promising paradigm for diverse control of the compositions and hydrophobicity of Cu‐based catalysts for selective CO 2 electroreduction to C 2+ products.