Single atom and defect engineering of CuO for efficient electrochemical reduction of CO₂ to C₂H₄

Abstract

Abstract Electrochemical CO 2 transformation to high‐value ethylene (C 2 H 4 ) at high currents and efficiencies is desired and yet remains a grand challenge. We show for the first time that coupling single Sb atoms and oxygen vacancies of CuO enable synergistic electrocatalytic reduction of CO 2 to C 2 H 4 at low overpotentials. Highly dispersed Sb atoms occupying metal substitutional sites of CuO are synthesized under mild conditions. The overall CO 2 reduction faradaic efficiency (FE) reaches 89.3 ± 1.1% with an FE toward C 2 H 4 exceeding 58.4% at a high‐current density of 500 mA/cm 2 . Addition of the p‐block metal is found to induce transformation of CuO from flakes to nanoribbons rich in nanoholes and oxygen vacancies, greatly enhancing CO 2 adsorption and activation while suppressing hydrogen evolution. Further density functional theory calculations with in situ X‐ray diffraction reveal that combining Sb sites and oxygen vacancies prominently lessen the dimerization energy of adsorbed CO intermediate, thus boosting the conversion of CO 2 to produce C 2 H 4 . This study provides a new perspective for promoting selective C–C coupling for electrochemical CO 2 reduction.