Effect of Mixed Valence Cu-In Bimetallic Oxides on Promoting Electrocatalytic Reduction of CO₂ to CO

The emission of carbon dioxide represents a severe threat to human survival. To alleviate this predicament, converting CO₂ into high-value products through electrocatalysis is a promising option. This study investigated the electrocatalytic performance of Cu-In bimetallic oxide, CuO, and In₂O₃, which were synthesized by a hydrothermal synthesis followed by calcination method. The catalysts were characterized by X-ray Diffraction, X-ray Photoelectron Spectroscopy, X-ray Absorption Spectroscopy,Scanning Electron Microscopy,Transmission Electron Microscopy and Density Functional Theory. The composition, structure, distribution and valence of elements, surface morphology, specific surface area and pore size of the catalyst were analyzed. Their electrocatalytic performance for CO₂ electrocatalytic reduction reaction was evaluated. The findings revealed that the Cu-In bimetallic mixed oxide exhibits a mixed valence state of Cu⁺ and Cu²⁺ for the Cu element. The distinctive elemental composition and optimized valence state distribution of the catalyst were found to significantly enhance its electrochemical performance in the electrocatalytic reduction of carbon dioxide toward CO production. When operated at an applied potential of -0.8 V vs. RHE, efficiency of 95.82%, demonstrating excellent hydrogen suppression and high CO selectivity.