Facile Synthesis of Cu-Doped In ₂ S ₃ Microflower Catalyst for Electrochemical CO ₂ Reduction to Energy Fuels in a Wide Potential Range

Enhancing the activity of electroreduction of CO 2 to valuable products and suppressing the hydrogen evolution reaction in aqueous solution are the major challenges nowadays for researchers. Indium-based materials demonstrate excellent catalytic behavior toward CO 2 electroreduction, and incorporation of the Cu element into In 2 S 3 brings better catalytic properties, provides enhanced electrochemical surface area, and provides higher charge transfer ability compared to the pristine material. Electrocatalytic techniques of the Cu doped In 2 S 3 were performed in an H-cell reactor, and the most efficient electrocatalyst was identified for the CO 2 reduction study. The electrocatalyst, 5% Cu doped In 2 S 3, can reduce CO 2 to methanol and formate with 34 and 36% Faradaic Efficiency (%FE), respectively, at −1.331 V vs RHE, and the corresponding partial current density values are −11.96 and −10.83 mA/cm 2 . The remarkable stability of the electrocatalyst during a 50 h of long-term chronoamperometry test further illustrates the excellent efficiency of the electrocatalyst. Density functional theory (DFT) based computational studies were employed to calculate the Density of States (DOS) of pristine In 2 S 3 and 5% Cu doped In 2 S 3 catalysts, as well as the free energies of intermediate product species for the generation of different carbon-based products.