Ultrafast Electron Transfer Coupled with a Proton Relay in an Anisotropic Dual S‐Scheme Heterojunction for Overcoming Kinetics Mismatch in H ₂ O ₂ Photosynthesis

The kinetic mismatch between electron transfer and proton diffusion fundamentally limits the efficiency of photocatalytic H₂O₂ production. To address this, an anisotropic dual S-scheme heterojunction (C₃N₄/SubPc-1/C₃N₅) is constructed to achieve spatiotemporal synergy between charge and proton transport. This multidimensional design establishes a tridirectional (lateral, vertical, and internal) charge transfer network, enabling ultrafast electron migration. Simultaneously, the ─CONH─ bridge acts as a dual channel for concurrent electron and proton transfer. Coupled with a Yeager-type oxygen adsorption configuration that preferentially activates a dual-pathway 2e^- oxygen reduction reaction (ORR), the optimized catalyst achieves an exceptional H₂O₂ production rate of 2048.7 µmol·g^- ¹·h^-1 and an apparent quantum yield of 16.28% at 400 nm. A combination of synchrotron radiation X-ray photoelectron spectroscopy (SI-XPS), femtosecond transient absorption spectroscopy (fs-TAS), and multiscale theoretical calculations -including density functional theory (DFT), time-dependent density functional theory (TDDFT), and molecular dynamics (MD) simulations- collectively reveals that the <1 ps anisotropic dual S-scheme electron transfer mechanism works synergistically with the proton relay function to efficiently drive charge separation and reactant activation. This study provides a universal interfacial engineering paradigm for managing complex proton-coupled electron transfer (PCET) processes in artificial photosynthesis.