Dual‐Channel Charge Transfer in Olefin‐Linked Covalent Organic Frameworks for Efficient Photocatalytic Hydrogen Evolution from Seawater

Abstract Covalent organic frameworks (COFs) represent promising candidates for solar‐driven hydrogen (H 2 ) production via water splitting, yet the performance remains constrained by intrinsically inefficient charge transfer dynamics. Herein, a rationally engineered 2D olefin‐linked COFs is presented, featuring dual‐channel charge transfer (i.e., in‐plane and interlayer) pathways for efficient photocatalytic H 2 evolution from seawater. Through systematic modulation of π ‐electron density distribution in electron donor–acceptor units, the optimized fully π ‐conjugated TTh‐Ph‐COF exhibits exceptional charge separation and transfer kinetics. Comprehensive density functional theory (DFT) calculations indicate that the in‐plane charge transfer is accelerated by sp 2 C═C linked bridges with a large dipole moment (8.71 Debye), while vertically aligned π – π stacking interactions facilitate interlayer charge migration. This synergistic dual‐channel electronic transport architecture enables TTh‐Ph‐COF to achieve a remarkable H 2 ‐evolution rate of 28.38 mmol h −1 g −1 in seawater and 55.36 mmol h −1 g −1 in deionized water, along with 20.31% apparent quantum efficiency at 420 nm irradiation. This research presents a novel design strategy aimed at enhancing light conversion efficiency within the molecular engineering framework through multi‐channel charge transfer systems.