Converting greenhouse gas carbon dioxide (CO2) to value-added chemicals is an appealing approach to tackle CO2 emission challenges. The chemical transformation of CO2 requires suitable catalysts that can lower the activation energy barrier to minimize the energy penalty associated with the CO2 reduction reaction. First-row transition metals are potential candidates as catalysts for electrochemical CO2 reduction; however, their high oxygen affinity makes them easy to be oxidized, which could strongly affect the catalytic properties of metal-based catalysts.[1] Recently, we proposed a strategy to synthesize ultra-thin electrocatalysts using a core-shell nanostructure that contains a bimetallic core responsible for high electronic conductivity and an ultra-thin partially oxidized shell for catalytic CO2 conversion. In this presentation, we will show a model core-shell electrocatalyst that has a silver-tin bimetallic core and an ultra-thin partially oxidized tin oxide shell (denoted as AgSn/SnOx) for CO2 reduction to formate with high Faradaic efficiencies and high current densities.[2] A structure-activity correlation between the AgSn/SnOx core-shell structure and CO2 electrocatalytic activity was established by studying a series of Ag-Sn catalysts with different Ag/Sn compositions. More importantly, a volcano-like correlation between the bulk composition and electrocatalytic performance was observed, in which the optimal thickness of the partially oxidized SnOx shell was ~1.7 nm.

Bimetallic catalyst with a core-shell structure for CO2 reduction

256th National Meeting (2018)

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