Interlayer interaction modulation via dihedral angle engineering in tetrazine COFs boosts charge transfer for photocatalytic H2O2 production

Covalent organic frameworks (COFs) show promise for solar-driven hydrogen peroxide (H 2 O 2 ) photosynthesis, but are limited by inefficient interlayer charge transport. Here, this study leverages non-covalent interactions arising from steric hindrance to gradually replace alternating C atoms in the central aryl ring of a triphenylarene platform with N atoms, thereby designing and synthesizing a series of tetrazine-based COFs (Tz-COF-N x ). The results show that as the number of N atoms in the COFs backbone increases, the dihedral angle between adjacent aromatic rings progressively decreases. The strengthened interlayer π - π interactions shorten the electron migration distance between layers and significantly improve the separation and migration efficiency of photogenerated charge carriers. The interlayer electron transfer numbers follow the trend: Tz-COF-N 3 (0.021 e − ) > Tz-COF-N 2 (0.011 e − ) > Tz-COF-N 1 (0.006 e − ) > Tz-COF-N 0 (0.001 e − ). Consequently, Tz-COF-N 3 achieves a photocatalytic H 2 O 2 production rate of 6316.4 μmol g −1 h −1 in pure water, which is 5.3 times higher than that of the benzene-tetrazine COF (Tz-COF-N 0 ). This study provides a feasible strategy for designing efficient COF-based photocatalysts by tuning the spatial configuration to optimize interlayer interactions and promote interlayer charge transport.