CuI / CuO Heterointerface Enables Selective Aqueous Electrosynthesis of 2‐Iodoxybenzoic Acid

Comprehensive Summary Aqueous electrosynthesis of hypervalent iodine(V) oxidants provides a sustainable and oxidant‐free alternative to conventional chemical synthesis, but the electrooxidation of 2‐iodobenzoic acid (IBA) to 2‐iodoxybenzoic acid (IBX) is limited by sluggish reaction kinetics and competitive oxygen evolution. Herein, we report a Cu(I)/Cu(II) heterointerface‐based CuI@CuO/CF electrocatalyst prepared by growing CuI@CuO on copper foam. The catalyst exhibits high selectivity for IBA electrooxidation in alkaline aqueous media, achieving 90.5% IBX selectivity and 71.4% Faradaic efficiency at 20 mA·cm –2 . Mechanistic studies and density functional theory calculations indicate that the CuI/CuO heterointerface promotes interfacial charge redistribution under anodic polarization, establishes a built‐in electric field, and favors the formation of high‐valent Cu–O(H)‐type surface states. These features facilitate the adsorption and activation of IBA‐derived species, reduce the energetic requirement of the reaction, and thereby contribute to the enhanced activity and selectivity. This work provides new insights into the rational design of highly active and selective electrocatalysts.