(66b) Ag-Sn Bimetallic Catalyst with a Core-Shell Structure for CO2 Reduction

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/SnO_x) for CO₂ reduction to formate with high Faradaic efficiencies and high current densities.[2] A structure-activity correlation between the AgSn/SnO_x 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 SnO_x shell was ~1.7 nm.

References:

1. Lu, Q., & Jiao, F.* Electrochemical CO₂ reduction: electrocatalyst, reaction mechanism, and process engineering. Nano Energy 29, 439-456 (2016).

2. Luc, W., Collins, C., Wang, S. W., Xin, H. L., He, K., Kang, Y. J. & Jiao, F.* Ag-Sn bimetallic catalyst with a core-shell structure for CO₂ reduction. Journal of the American Chemical Society 139, 1885-1893 (2017).