Dynamic Restructuring of Cu-Doped SnS₂ Nanoflowers for Highly Selective Electrochemical CO₂ Reduction to Formate

With ever-increasing energy consumption and continuous rise in atmospheric CO₂ concentration, electrochemical reduction of CO₂ into chemicals/fuels is becoming a promising yet challenging solution. Sn-based materials are identified as attractive electrocatalysts for the CO₂ reduction reaction (CO₂ RR) to formate but suffer from insufficient selectivity and activity, especially at large cathodic current densities. Herein, we demonstrate that Cu-doped SnS₂ nanoflowers can undergo in situ dynamic restructuring to generate catalytically active S-doped Cu/Sn alloy for highly selective electrochemical CO₂ RR to formate over a wide potential window. Theoretical thermodynamic analysis of reaction energetics indicates that the optimal electronic structure of the Sn active site can be regulated by both S-doping and Cu-alloying to favor formate formation, while the CO and H₂ pathways will be suppressed. Our findings provide a rational strategy for electronic modulation of metal active site(s) for the design of active and selective electrocatalysts towards CO₂ RR.