Efficient carbon dioxide electroreduction over rationally designed heterogeneous Ag2S-Au nanocomposites

Electrochemical carbon dioxide reduction reaction (CO 2 RR) is regarded as an effective strategy to store abundant renewable energy and build a carbon neutral society. Gold (Au) and silver (Ag)-based catalysts for the effective electrochemical transformation of CO 2 to CO emerge as promising candidates. Heterogeneous nanocomposites composed of noble metals and semiconductors exhibit great potential for electrocatalytic CO 2 reduction through the electronic coupling effect at coherent interfaces. Herein, we successfully synthesize heterogeneous Ag 2 S-Au composite nanoparticles (NPs) as effective catalysts for CO production through CO 2 RR. At −0.8 V vs RHE, the heterogeneous Ag 2 S-Au nanocatalysts display a considerable CO Faradaic efficiency of 94.5%, and an appreciable CO partial current density of 9.17 mA cm −2 . Moreover, they exhibit good stability for 30 h without obvious decrease. On the basis of density functional theory (DFT) calculations, it can be made clear that the heterogeneous Ag 2 S-Au interface is energetically more beneficial to the generation of COOH* intermediate for CO 2 RR. This study provides a new application for noble metal–semiconductor nanocomposites.