Dynamic Hydrogen‐Bonding Nanonetworks and Asymmetric Dual‐Interface Built‐In Electric Fields Cooperatively Mediate Proton‐Coupled Electron Transfer for C─H Activation

C─H bond activation represents a ubiquitous transformation in chemistry, yet challenging owing to the complex requirements for proton and electron transfer. A general strategy for constructing proton-electron dual-transport-channel photocatalysts: hollow hierarchical Co₃S₄/Sv-chalcogenide/Ti₃C₂ nanoreactors (Sv = sulfur vacancies, chalcogenide = CdIn₂S₄, ZnIn₂S₄, CdS) is developed via lateral epitaxy and defect-mediated heterocomponent anchorage. These ternary-component nanoreactors integrate dynamic hydrogen-bonding nanonetworks and asymmetric dual-interface built-in electric fields (BIEFs), acting as the strong proton/electron extractors for steering proton-coupled electron transfer (PCET) in C─H activation of biomass-derived molecules. The BIEFs-induced electron transport channel is featured by powerful photocarrier enrichment and feeble photocarrier recombination at Co₃S₄/chalcogenide S-scheme heterointerface, and photocarrier localization and delocalized-electron transport at Sv-chalcogenide/Ti₃C₂ Schottky heterointerface. The hydrogen bond network-induced proton transport channel lies in electron-enriched interfacial lattice oxygen for mediating the substrate deprotonation via nucleophilic abstraction, and the hydrophilic MXene for guiding proton transfer along modified dynamic hydrogen-bonding nanonetworks. By virtue of dynamically optimized molecular catalytic behavior accomplished by pivotal intermediate adsorption/activation regulation, representative Co₃S₄/Sv-CdIn₂S₄/Ti₃C₂ HNR exhibits remarkable C─H activation performance and broad substrate compatibility. This work establishes a pioneering paradigm for manipulating proton-electron dual-transport-channel by hydrogen-bonding nanonetworks and BIEFs, offering novel strategies for regulating molecular catalytic behavior in complex reaction pathways.