Harnessing S-scheme BiOCl/COF heterojunctions for sustainable and efficient photocatalytic hydrogen peroxide synthesis under visible light

Photocatalytic hydrogen peroxide production offers a greener alternative, but its efficiency is limited by high carrier recombination. Covalent organic frameworks, with their highly ordered structures and tunable properties, are promising photocatalysts. However, their application in H 2 O 2 production has been constrained by the lack of effective strategies to enhance catalytic activity. In this study, BiOCl/COF (TFPB-BPY) S-scheme heterojunctions were prepared via a simple in-situ growth method. The heterojunction exploits the nitrogen-rich architecture and charge transport of the COF, combined with the broad light absorption and internal electric field of BiOCl. This synergy enables superior visible light absorption, efficient charge separation, and suppressed recombination. Mechanistic studies confirmed the S-scheme mechanism as the key to its enhanced performance. This work provides a scalable and eco-friendly strategy for improving COF-based photocatalysts through S-scheme heterojunctions, offering a pathway for sustainable H 2 O 2 production and advancing the rational design of photocatalysts for green energy applications.