Construction of COF/ultrathin carbon nitride heterojunctions for solar-driven high-efficiency photocatalytic H2O2 production

Graphitic carbon nitride (g-C 3 N 4 ) exhibits significant potential in photocatalytic hydrogen peroxide (H 2 O 2 ); however, its practical application is constrained by narrow spectral light absorption, high charge carrier recombination rates, and insufficient surface-active sites due to inherent structural defects. Herein, ultrathin carbon nitride (UCN) nanosheets were coupled with porphyrin-based covalent organic frameworks (COFs) via π-π interaction and H-bond to construct 2D COF/UCN heterojunctions. The optimized catalysts demonstrated a remarkable H 2 O 2 production rate of 418.93 μmol·g −1 ·h −1 under visible light, representing a 5.3-fold enhancement over intrinsic g-C 3 N 4 . Crucially, band structure analysis and in situ infrared spectroscopy confirmed that the heterojunction of enhanced interfacial charge migration and spatial separation facilitated efficient H 2 O 2 generation via a single-step two-electron oxygen reduction pathway (O 2 + 2H + + 2e - → H 2 O 2 ). This work demonstrates that heterojunction engineering synergistically optimizes light harvesting, charge separation, and surface reactions, providing a novel paradigm for carbon nitride modification and establishing a design platform for solar-driven H 2 O 2 production.