Synergistic effect of Cu/Cu2O surfaces and interfaces for boosting electrosynthesis of ethylene from CO2 in a Zn–CO2 battery

Abstract

Metal–carbon dioxide batteries have received considerable research interest because the technology not only can be used as clean energy storage devices, but also can achieve the conversion of carbon dioxide to produce useful fuels and chemicals. However, the development of high-performance electrocatalysts remains a major challenge. Here, we report the design and controllable construction of efficient Cu/Cu₂O electrocatalysts with synergy of active surfaces and interfaces for the conversion of carbon dioxide to ethylene. The highly active Cu/Cu₂O electrocatalysts are relatively stable under the condition of CO₂ electroreduction, and the synergistic effect of the Cu/Cu₂O surface and interface improves the selectivity and efficiency for C₂H₄ production. A high ethylene faradaic efficiency of 50% at −1.1 V vs. RHE on the Cu/Cu₂O catalyst is achieved. Moreover, Zn–CO₂ batteries equipped with the Cu/Cu₂O catalyst exhibit an energy density of up to 1.17 mW cm⁻², and can maintain a cycle stability of 24 hours. Theoretical calculations show that the surface/interface of catalysts can enhance the adsorption of *CO, and further promotes the dimerization of *CO to ethylene. In situ ATR-FTIR spectroscopy studies have also further confirmed that *CO is an important intermediate during the formation of C₂H₄. This research will provide a new strategy for improving the stability of C–C coupling products and CO₂ capture, conversion and electric power generation.