Crystalline‐Amorphous Interfaces Engineering of CoO‐InO_x for Highly Efficient CO₂ Electroreduction to CO

Abstract As a fundamental product of CO₂ conversion through two‐electron transfer, CO is used to produce numerous chemicals and fuels with high efficiency, which has broad application prospects. In this work, it has successfully optimized catalytic activity by fabricating an electrocatalyst featuring crystalline‐amorphous CoO‐InO_x interfaces, thereby significantly expediting CO production. The 1.21%CoO‐InO_x consists of randomly dispersed CoO crystalline particles among amorphous InO_x nanoribbons. In contrast to the same‐phase structure, the unique CoO‐InO_x heterostructure provides plentiful reactive crystalline‐amorphous interfacial sites. The Faradaic efficiency of CO (FE_CO) can reach up to 95.67% with a current density of 61.72 mA cm⁻² in a typical H‐cell using MeCN containing 0.5 M 1‐Butyl‐3‐methylimidazolium hexafluorophosphate ([Bmim]PF₆) as the electrolyte. Comprehensive experiments indicate that CoO‐InO_x interfaces with optimization of charge transfer enhance the double‐layer capacitance and CO₂ adsorption capacity. Theoretical calculations further reveal that the regulating of the electronic structure at interfacial sites not only optimizes the Gibbs free energy of *COOH intermediate formation but also inhibits HER, resulting in high selectivity toward CO.