Facile Synthesis of Indium-Doped Cuprous Oxide Catalyst for Enhanced Electrochemical Reduction of CO2 to CO

Electrochemical CO2 conversion into sustainable fuels and high-value chemicals represents a promising technology for producing valuable chemical products. However, the hydrogen evolution reaction (HER) becomes a major competing process during CO2 reduction reactions (CO2RR), posing significant challenges for catalyst design. In this study, Cu2O catalysts were synthesized via a simple one-pot hydrothermal method. The modification strategy of element doping was selected to design the catalyst. The Indium doping content was controlled through Cu/In ratio adjustment to modulate the selectivity of CO2 electrocatalytic reduction. Compared to In-free Cu2O, the Cu60In1 catalyst with an optimized Cu/In ratio exhibited enhanced CO2RR performance. At a low applied potential of −0.75V vs. RHE, the catalyst demonstrated a current density of −29.2mA·cm⁻2 with 80.3% CO selectivity, representing an approximately 10-fold enhancement over pure Cu2O. In-situ IR analysis and DFT calculations demonstrate that In-doped Cu2O exposes (111) crystal facets more prone to *COOH formation. This intermediate generates *CO, promoting CO desorption while suppressing the hydrogen evolution reaction (HER), enhancing both catalytic activity and CO selectivity in CO2 reduction.