Surface Oxide-Derived Nanoporous Gold Catalysts for Electrochemical CO₂-to-CO Reduction

Electrochemical CO2 reduction (ECR) has become a viable option as the cost of renewable energy continues to decrease. One of the major obstacles that prevents its widespread use is the lack of efficient ECR catalysts due to our only slowly emerging understanding of catalyst design. Here, we report on a surface oxide-derived nanoporous gold catalyst prepared by one-step electrochemical dealloying that shows an extremely low overpotential (Faradaic efficiency for CO exceeds 90%) of 0.185 V (−0.3 V vs RHE) for CO2-to-CO conversion in 0.1 M KHCO3 solution. We demonstrate that surface oxide-derived nanoporous gold shows improved ECR performance with higher Faradaic efficiency compared to clean nanoporous gold which is the consequence of its smaller overpotential for CO2-to-CO reduction and simultaneous suppression of hydrogen evolution.