Heterogeneous Structure of Sn/SnO₂ Constructed via Phase Engineering for Efficient and Stable CO₂ Reduction

The electrochemical carbon dioxide reduction reaction (CO₂RR) catalyzed by Sn-based materials shows great potential for CO₂-to-formate conversion. The presence of tin species with different oxidation states can promote the catalytic performance, most likely due to the interfaces of metallic and oxide phases that induce a synergistic effect. Therefore, it is desirable yet challenging to synthesize a hybrid catalyst with abundant active heterogeneous interfaces. Herein, we synthesize a hybrid catalyst constructed by decorating nanosized SnS₂ in the SnO₂ matrix. The uniformly distributed SnS₂ nanoparticles are first reduced to metallic tin, which assists in the generation of abundant Sn/SnO₂ heterogeneous interfaces under the in situ reduction process. Because of the electronic modulation at the heterogeneous interfaces, the resulting catalyst delivers a high current density of 200 mA·cm^-2 at -0.86 V vs RHE, and the performance is stable for over 20 h. This work suggests a potentially powerful interface engineering strategy for the development of high-performance electrocatalysts for the CO₂RR.