Electrochemical CO₂ to CO reduction at high current densities using a nanoporous gold catalyst

Abstract

We report on integrating ultrathin monolithic nanoporous gold (npAu) catalyst coatings for CO₂ reduction in a large electrode area (25 cm²) electrochemical membrane reactor with gas diffusion electrodes at 100 mA/cm². The CO Faraday efficiency increases with increasing thickness, from 65% to 75% and 80% for 1, 5, and 10 layers of npAu leaves where each npAu leaf layer is 100 nm thick. For the one npAu leaf layer configuration, this corresponds to an extremely high CO current density of 955 A/g gold thus demonstrating the potential for commercial applications. By device level optimization of catalyst integration we significantly improved the utilization of gold catalysts for electrochemical CO₂ reduction to syngas at industrial relevant current densities of 100 mA/cm².