Synergistic Effect of Bio‐Inspired Microenvironment Modulation and Catalytic Site Design Enhances the Oxygen Evolution Performance of Copper‐Phenanthroline Catalysts

ABSTRACT Copper complexes inspired by O ₂ ‐activating enzymes have been widely investigated as molecular water oxidation catalysts, capable of facile and reversible O─O bond formation and cleavage under mild conditions. In this study, two copper phenanthroline complexes, namely, Cu(phen) and Cu(dophen), exhibit high turnover frequencies (TOFs) of 74 ± 13 and (5.66 ± 0.29) × 10 ³ s ⁻¹ for water oxidation, respectively. Moreover, amino acid‐functionalized carbon dots (CDs) were used to support the adhesion of the [Cu] complexes onto the electrode, significantly enhancing the TOFs of (2.80 ± 0.12) × 10 ³ and (4.11 ± 0.24) × 10 ⁴ s ⁻¹ , respectively, exceeding the activity of photosystem II in nature. Remarkably, the amino acid‐functionalized CDs provide a secondary sphere that mimics the catalytic microenvironment of the copper centre, which promotes proton‐coupled electron transfer and O─O bond formation. Finally, the photovoltaic‐electrolysis (PVE) system was established using CDs‐supported Cu catalysts and commercial silicon solar panels, achieving a high solar‐to‐hydrogen efficiency of 11.59% under the illumination of AM 1.5 G. This represents the most efficient solar‐driven water splitting system based on copper‐based catalysts to date, introducing the biomimetic secondary sphere to a “proton‐rocking” process for water oxidation catalysis and application of the PVE system.