Halogen-incorporated Sn catalysts for selective electrochemical CO₂ reduction to formate

Electrochemically reducing CO2 to valuable fuels or feedstocks is recognized as a promising strategy to simultaneously tackle the crises of fossil fuel shortage and carbon emission. Sn-based catalysts have been widely studied for electrochemical CO2 reduction reaction (CO2 RR) to make formic acid/formate, which unfortunately still suffer from low activity, selectivity and stability. In this work, halogen (F, Cl, Br or I) was introduced into the Sn catalyst by a facile hydrolysis method. The presence of halogen was confirmed by a collection of ex situ and in situ characterizations, which rendered a more positive valence state of Sn in halogen-incorporated Sn catalyst as compared to unmodified Sn under cathodic potentials in CO2 RR and therefore tuned the adsorption strength of the key intermediate (*OCHO) toward formate formation. As a result, the halogen-incorporated Sn catalyst exhibited greatly enhanced catalytic performance in electrochemical CO2 RR to produce formate.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)This work was supported by the fund from NUS Green Energy Program (WBS:A-0005323-05-00), FRC MOE T1 (WBS:A-0009184-00-00), A*STAR LCERFI Project (Award ID: U2102d2011),Ministry of Education of Singapore (Tier 1: RG4/20, RG2/21 and Tier 2: MOET2EP10120-0002), Agency for Science, Technology and Research (AME IRG: A20E5c0080),the National Natural Science Foundation of China (Grant No. 22075195), and Photon Science Research Center for Carbon Dioxide