In Situ Electrodeposited Indium Nanocrystals for Efficient CO2 Reduction to CO with Low Overpotential

The dream of artificial photosynthesis that converts CO2 to fuels or chemicals has been dimmed by the lack of efficient catalysts. Herein, an indium (In)-based catalyst is prepared via in situ electrodeposition on a carbon substrate from an organometallic precursor during the CO2 reduction reaction. It is found to be robust for CO2 reduction to CO promoted by imidazolium ionic liquid in acetonitrile. The onset overpotential is impressively low for a non-noble-metal material, rivaling that of the noble metal Ag. Moreover, the CO evolution rate is stable for 15 h, with a Faradaic efficiency of around 99%. Under the same conditions, In catalyst deposited in situ performs much better than that prepared ex situ and most of the catalysts previously reported. This is ascribed to the intrinsic properties of in situ generated In nanocrystals in good contact with the porous substrate, suggesting the advantages of the in situ preparation strategy. In addition, via coupling the CO2 reduction reaction with water oxidation in aqueous anolyte, CO and O-2 can be produced simultaneously with high efficiency, demonstrating the good performance of the non-noble-metal In-based catalyst for reducing CO2 to CO and its possible application in artificial photosynthesis from water and CO2.