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 Inδ+ species under catalytic conditions. This work presents an approach for efficient formate electrosynthesis through the simultaneous modulation of catalyst interfacial structure and coupling reactions.