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

Copper-based electrocatalysts are recognized as crucial catalysts for CO2 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/Cu2O heterostructure is constructed by adjusting the anion species of the Cu ions-containing electrolyte during electrodeposition synthesis. Then, Cu/Cu2O with tuned nanoarchitectures ranging from dendrites to polyhedrons is achieved by introducing transition metal ions as additives, leading to an adjustable interfacial microenvironment for CO2/H2O adsorption on the Cu/Cu2O electrodes. Additionally, the polyhedral Cu/Cu2O catalysts are used as templates for depositing Ag single atoms (AgSA), which are known as synergistic active sites for promoting *CO to *COH toward C2+ products. The prepared AgSA-Cu/Cu2O catalyst is evaluated in a flow cell and exhibited a FEC2+ of 90.2% and a partial current density (jc2+) of 426.6 mA cm-2 for CO2 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 CO2 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 CO2 electroreduction to C2+ products.