Regulating p-orbital electronic configuration of In2O3 by thickness-controlled carbon layer for efficient electrocatalytic CO2 reduction to HCOOH

As for developing efficient Indium (In)-based catalyst of CO reduction to HCOOH, the modulation of electronic structure stands as a pivotal factor. However, the precise control of -orbital electronic configuration of InO remains challenging. Herein, the carbon-coated InO (InO@C) with precisely controllable carbon thickness is developed. The InO modified by moderate carbon layer thickness exhibits an impressive FE exceeding 90 % and maintains a constant current density of 110 mA cm even after 100 h. Meanwhile, it achieves a FE of 97 % and a current of 550 mA in a membrane electrode assembly. The catalyst maintains satisfactory activity even under low CO concentration and acidic electrolytes. The density functional theory (DFT) calculations show that carbon layer successfully improves the -orbital electronic configuration of InO and perfects the adsorption energy of *OCHO intermediate. This work can provide a guidance for regulating electronic configuration and designing high-efficiency electrocatalyst.