Electron Localization‐Triggered Proton Pumping Toward Cu Single Atoms for Electrochemical CO2 Methanation of Unprecedented Selectivity

Abstract

AbstractSlow multi‐proton coupled electron transfer kinetics and unexpected desorption of intermediates severely hinder the selectivity of CO2 methanation. In this work, a one‐stone‐two‐bird strategy of pumping protons and improving adsorption configuration/capability enabled by electron localization is developed to be highly efficient for CH4 electrosynthesis over Cu single atoms anchored on bismuth vacancies of BiVO4 (Bi1‐xVO4─Cu), with superior kinetic isotope effect and high CH4 Faraday efficiency (92%), far outperforming state‐of‐the‐art electrocatalysts for CO2 methanation. Control experiments and theoretical calculations reveal that the bismuth vacancies (VBi) not only act as active sites for H2O dissociation but also induce electron transfer toward Cu single‐atom sites. The VBi‐induced electron localization pumps *H from VBi sites to Cu single atoms, significantly promoting the generation and stabilization of the pivotal intermediate (*CHO) for highly selective CH4 electrosynthesis. The metal vacancies as new initiators show enormous potential in the proton transfer‐involved hydrogenative conversion processes.