Engineering the CuO–HfO2 interface toward enhanced CO2 electroreduction to C2H4

Abstract

We report significantly enhanced electrochemical CO₂ reduction (ECR) to C₂H₄ by tuning the interface of a metal oxide composite (CuO_x/HfO₂), enabling a C₂H₄ faradaic efficiency as high as 62.6 ± 1.3% at 300 mA cm⁻², in contrast to only 11.6 ± 1.6% over pure CuO. Collective knowledge from multiple control experiments, density functional theory calculations, and operando Raman study reveals that the CuO_x–HfO₂ interface greatly strengthens CO₂ adsorption and the binding of *CO for further C–C coupling to yield C₂H₄.