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

The electrochemical carbon dioxide reduction reaction (CO 2 RR) catalyzed by Sn-based materials shows great potential for CO 2 -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 SnS 2 in the SnO 2 matrix. The uniformly distributed SnS 2 nanoparticles are first reduced to metallic tin, which assists in the generation of abundant Sn/SnO 2 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 CO 2 RR.