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

Abstract

Electrochemical synthesis of multicarbon (C₂₊) liquid products from CO₂ is one of the key technologies for establishing a carbon-neutral society. To improve the selectivity for C₂₊ products, a two-step cascade reaction has been proposed; CO₂ is first reduced to CO followed by further reduction to C₂₊ products. However, conventional Cu-based catalysts predominantly yield gaseous products, such as C₂H₄ in the CO reduction step, thereby capping the selectivity for C₂₊ liquids. In this study, Ag nanoparticles introduced onto Cu₂O nanocubes (Ag-Cu₂O NC) were developed to improve the selectivity toward C₂₊ liquid products in the CO reduction. The Ag-Cu₂O NC demonstrated an exceptionally high Faradaic efficiency of 54% for C₂₊ liquid products at a partial current density of 108 mA/cm², approximately twice as high as that of the gaseous products, while suppressing C₂H₄ formation. The catalyst morphology exhibited a Ag⁰-Cu⁰ composite with Ag nanoparticles highly dispersed on the surfaces of metal Cu particles during the CO electrolysis. Thus, the configuration of Ag⁰ and Cu⁰ facilitates the selective formation of C₂₊ liquid products. The present study highlights an effective strategy for materials design to improve the selectivity toward C₂₊ liquid products in electrochemical CO reduction through the introduction of a second metal.