Functional Group‐Regulated Interfacial Electronic Coupling Enables Efficient Oxygen Evolution on Nickel Catalysts

ABSTRACT Facilitating the sluggish oxygen evolution reaction (OER) is crucial for sustainable electrochemical hydrogen production, yet molecular‐level regulation of interfacial electronic coupling remains insufficiently understood, particularly in functional‐group‐engineered catalysts. In this study, we report a conjugation‐dependent interfacial electronic coupling strategy to regulate the electronic structure of NiO supported on single‐walled carbon nanotubes. By introducing carboxyl groups (─COOH) or carboxymethyl groups (─CH 2 COOH) by inserting a methylene spacer (─CH 2 ─) into ─COOH, the interfacial electronic contact can be precisely tuned, enabling direct comparison of conjugated and interrupted coupling interfaces. The optimized COOH‐NiO achieved a mass activity of 730 A g −1 , significantly outperforming its CH 2 COOH counterpart (111 A g −1 ). This result highlights the importance of functional group regulation in optimizing Ni active sites to enhance OER performance. Combined in situ electrochemical spectroscopy and theoretical analyses reveal that enhanced interfacial electronic coupling induces charge redistribution at Ni active centers, thus optimizing the d‐band center and accelerating the evolution of γ‐NiOOH‐like reconstructed species. Notably, the weakened adsorption strength of * OH on COOH‐NiO enables a higher evolution of * OOH, thereby lowering the kinetic barriers of OER. This work establishes functional‐group‐controlled interfacial electronic coupling as a general strategy for developing efficient non‐noble metal electrocatalysts in sustainable energy technologies.