Effects of Ag Nanoparticle Coated Metal Electrodes on Electrochemical CO₂ Reduction in Aqueous KHCO₃

Electrochemical CO2 reduction is crucial for developing a sustainable closed-carbon-cycle society; however, the factors determining product selectivity have not been fully established, especially when the reaction is carried out over metal cathodes. The selectivity of the CO2 reduction pathway can be improved by modifying the cathode's catalyst surface. This can be achieved by using specific surface of single crystal or by alloying through the addition of an impurity. In this study, the products of electrochemical CO2 reduction were evaluated in an aqueous KHCO3 system at various applied currents and with various metal cathodes. The metal cathodes were coated by Ag nanoparticles, as the Ag cathode was determined to yield the best Faradaic efficiency for CO production in an aqueous KHCO3 system. Our results suggest that some Ag coated cathodes enhance CO2 reduction, and thus the reduction products are tunable through surface modification. (C) The Author(s) 2021. Published by ECSJ.