Nanodendritic Ag catalyst coated on gas diffusion electrode for highly efficient CO 2 electroreduction to CO

Abstract Currently, global warming and ocean acidification are attributed to the excess of CO 2 in the atmosphere. Catalyst-assisted electroreduction is a promising approach to convert CO 2 into various products, mitigating the existing CO 2 . CO itself is a source for synthesis of chemicals, and is considered a unique intermediate for further reduction to valuable multi-carbon products such as C 2 H 4 and C 2 H 5 OH. Nanostructured Ag acts as a good catalyst in the CO 2 electrochemical reduction process to produce CO. This article presents the synthesis of Ag nanodendrites (AgNDrs), their characteristics, and their performance in the CO 2 electrochemical reduction process. The main advantage presented in this study is the use of a simple aqueous electrodeposition method to synthesize AgNDrs directly on the gas diffusion electrode (GDE). The AgNDr-coated GDEs work well for highly selective and efficient electroreduction of CO 2 to CO, competing effectively against proton reduction. The ratio of CO/H 2 production can be tuned via the material synthesis conditions or the applied cathodic potentials during CO 2 reduction. Electroreduction of CO 2 to CO in a fully aqueous solution achieves a Faradaic efficiency of 90% at a potential of −1.2 V versus RHE and maintains during 4 h electrolysis.