Stabilized High‐Valent Indium for Promoted Formate Production from Electrochemical CO2 Reduction

Abstract

AbstractElectrocatalysts based on high‐valent indium are promising for formate production via CO2 electroreduction. However, reconstruction often occurs during the reaction progress, resulting in a decline in catalytic performance. Here, a composite of In2O3/In2S3 is developed, and its catalytic performance exceeds that of either individual phase, particularly in stability. Analysis of morphology, valence state, and in situ Raman spectroscopy reveals that In2O3 is well preserved during the reaction. Theoretical calculations suggest that the desorption energy of lattice oxygen on In2O3 can be strengthened due to In2O3‐In2S3 bonding within the composite. This reinforcement facilitates the formation of more active sites and promotes CO2 adsorption, further decreasing the energy barrier of formate production to only 0.12 eV. As a result, the composite exhibits a formate selectivity over 95.05% at –1.13 V vs reversible hydrogen electrode accompanied by a partial current density of 434.4 mA cm–2. Notably, the selectivity of formate maintains over 95% even after 50 h at an industrial‐level current density of 200 mA cm–2, 17 times longer than the individual phase. Furthermore, 18.33% solar‐to‐formate and 19.49% solar‐to‐fuel are obtained when coupled with III‐V solar cells, demonstrating its feasibility.