Confinement-Stabilized High-Valent Indium for pH-Universal Electrocatalytic CO₂ Reduction

The integration of electrocatalytic carbon dioxide reduction (CO₂) with biomass valorization for the production of high-value chemicals presents a promising strategy for achieving carbon neutrality. Herein, we synthesized a nitrogen-carbon layer (NC layer) confined indium oxide (In₂O₃) to enhance the electrochemical CO₂ reduction activity, concurrently coupling with the anodic formaldehyde oxidation reaction to achieve simultaneous electrosynthesis of formate in both cathode and anode compartments. Confinement within the NC layer significantly improves the formate selectivity of In₂O₃ while maintaining a high catalytic stability across a wide pH range. Density functional theory (DFT) calculations reveal that the work function difference between the NC layer and the In₂O₃ induces strong electronic interactions and stabilizes the In^δ+ species under catalytic conditions. This work presents an approach for efficient formate electrosynthesis through the simultaneous modulation of catalyst interfacial structure and coupling reactions.