Reconstruction-Driven YO6–Sn Interactions in Y-Doped SrSnO3 for Stable Acidic CO2-to-HCOOH Electrocatalysis at Industrial Current Densities

Abstract

Electrocatalytic CO2 reduction to formic acid is a promising route for mitigating CO2 emissions and producing value-added chemical feedstocks. However, achieving industrially relevant activity and stability in acidic media remains challenging due to severe hydrogen evolution, catalyst corrosion, and structural degradation. Herein, we report a rare–earth yttrium-doped SrSnO3 perovskite oxide (SrSn0.7Y0.3O3) synthesized via a solid-state reaction method. The incorporation of YO6 octahedra induces in situ electrochemical reconstruction of SnO6 units into metallic Sn, leading to the formation of strong YO6–Sn interfacial interactions that modulate the electronic structure of Sn active sites and enhance their structural stability. The optimized reconstructed catalyst, denoted as c–SrSn0.7Y0.3O3, delivers a Faradaic efficiency of over 90% for formic acid at an industrially relevant current density of 200 mA cm-2 under acidic conditions, while maintaining outstanding operational durability for over 180 h without observable performance decay. Mechanistic investigations reveal that the strong interaction between in situ generated metallic Sn and YO6 units effectively suppresses Sn dissolution and crystal structural collapse, thereby ensuring long-term stability in acidic media. This work demonstrates a rare-earth doping and electrochemical strategy that achieves a well-integrated balance of activity, selectivity, and stability, offering a promising pathway for advancing acidic CO2 electroreduction toward industrial application.