Regional topological engineering of imine/hydrazone COFs enables acid-free photoinduced self-protonation for photocatalytic H2O2 production

Regional topological regulation of charge transport and proton-transfer dynamics. • Acid-free photoinduced self-protonation and cooperative proton transfer. • Catalytic and preparative validation of the proposed strategy. The inherent trade-off between electron transport efficiency and proton transfer dynamics in COFs is a fundamental limitation for its application in photocatalysis. Herein, we report a regionalized topology engineering strategy that molecularly programs the stoichiometric ratio and regional arrangement of imine and hydrazone linkages within DABH-COF, thereby coordinating charge transport and proton-transfer kinetics. This tailored structure enables photo-triggered protonation under visible light, whereby dynamic imine bonds undergo in-situ protonation to create a proton-rich microenvironment that favors the 2e − ORR, while adjacent hydrazone bonds facilitate rapid proton transfer through a hydrogen-bond network. DFT calculations show that this cooperative effect lowers the free-energy requirement for *OOH formation from 0.26 to 0.20 eV during the 2e − ORR, thereby favoring electron–proton transfer. Moreover, the achievement of gram-scale synthesis (1.2 g) of highly crystalline DABH-COF addresses scalability challenges in COF production. DABH-COF exhibits a superior visible-light-driven H 2 O 2 -production rate of 4340 μmol g −1  h −1 without any sacrificial agents and an AQY of 12.4% (420 nm). This study provides a way for constructing effective COF-based photocatalysts through regional topology engineering. Through regionalized topology engineering, the imine and hydrazone bonds are molecularly programmed by monomer connectivity within DABH-COF, which enables in-situ protonation and synergistical electron–proton dynamics for high-performance photocatalysis. Download: Download high-res image (159KB) Download: Download full-size image