Orchestrating Proton-Coupled Electron Transfer in Atomically Wired SubPc-CuBTC-NH ₂ Heterostructure for Panchromatic Photocatalytic Cascade Reactions

Proton-coupled electron transfer (PCET) is pivotal for photocatalytic H 2 O 2 synthesis yet remains constrained by the slow kinetics of water oxidation, which impedes synchronous proton supply. Herein, a triple-site photocatalyst (SubPc1-CuBTC-NH 2 ) was constructed where thermodynamically unfavorable water oxidation is supplanted by efficient tetracycline oxidation, thereby redirecting the PCET pathway. The covalent amide bridge functions as a dual channel for electron transfer and proton relay, reducing the proton-transport activation energy by 57% and the electron-transfer barrier by 35%, compared to pristine CuBTC-NH 2 . Under simulated sunlight, the composite achieves an H 2 O 2 production rate of 2091.5 μmol·g −1 ·h −1, representing a 7.5-fold enhancement over the pristine CuBTC-NH 2 . Coupling with tetracycline degradation further elevates the H 2 O 2 yield to 5517.4 μmol·g −1 ·h −1 while enabling >99.8% pollutant removal. Mechanistic insights reveal that Cu sites oxidize pollutants to release protons, the amide bridge facilitates interfacial electron and proton transport, and the SubPc1 macrocycle selectively reduces O 2 to H 2 O 2 through a synchronized PCET process. This study illustrates how covalent interface engineering can precisely program proton-electron spatiotemporal dynamics, establishing a material paradigm for efficient artificial photosynthesis beyond conventional water-oxidation limitations.