Introduction of Ag Nanoparticles onto Cu Catalysts Enhances the Selectivity toward Multicarbon Liquid Products in Electrochemical CO Reduction

Electrochemical synthesis of multicarbon (C 2+ ) liquid products from CO 2 is one of the key technologies for establishing a carbon-neutral society. To improve the selectivity for C 2+ products, a two-step cascade reaction has been proposed; CO 2 is first reduced to CO followed by further reduction to C 2+ products. However, conventional Cu-based catalysts predominantly yield gaseous products, such as C 2 H 4 in the CO reduction step, thereby capping the selectivity for C 2+ liquids. In this study, Ag nanoparticles introduced onto Cu 2 O nanocubes (Ag-Cu 2 O NC) were developed to improve the selectivity toward C 2+ liquid products in the CO reduction. The Ag-Cu 2 O NC demonstrated an exceptionally high Faradaic efficiency of 54% for C 2+ liquid products at a partial current density of 108 mA/cm 2, approximately twice as high as that of the gaseous products, while suppressing C 2 H 4 formation. The catalyst morphology exhibited a Ag 0 -Cu 0 composite with Ag nanoparticles highly dispersed on the surfaces of metal Cu particles during the CO electrolysis. Thus, the configuration of Ag 0 and Cu 0 facilitates the selective formation of C 2+ liquid products. The present study highlights an effective strategy for materials design to improve the selectivity toward C 2+ liquid products in electrochemical CO reduction through the introduction of a second metal.