Heteroatom-Bridged Covalent Organic Frameworks for Efficient Solar-Driven H2O2 Production through Tailored Electronic Structures

Abstract

Covalent organic frameworks (COFs) exhibit significant potential for solar-driven H₂O₂ synthesis but are intrinsically limited by inefficient charge separation and sluggish oxygen reduction reaction kinetics. In this study, we developed a heteroatom-bridging strategy for the precise atomic engineering of pyrene-based COFs (PX-COFs, X = C/O/S). The strategic substitution of bridging atoms with oxygen or sulfur effectively modulates the electronic configuration and optimizes reaction thermodynamics. The resulting PO-COF demonstrates an exceptional visible-light-driven H₂O₂ production rate of 3446.3 μmol g^–1 h^–1, surpassing the performance of most reported COF-based photocatalysts. Comprehensive characterization combined with density functional theory calculations reveals that the superior activity arises from synergistic effects: enhanced light harvesting, thermodynamically favorable O₂ adsorption coupled with a reduced energy barrier for *OOH intermediate formation, and accelerated interfacial charge transfer kinetics. Crucially, we establish a clear correlation between the electronegativity of the bridging heteroatom and the photocatalytic activity, identifying oxygen as uniquely capable of synchronizing light harvesting, charge separation, and surface catalysis. This work provides fundamental insights for the rational design of highly efficient COF-based photocatalysts to advance solar-to-chemical energy conversion.