Engineering modular and tunable the overall photocatalytic generation of H 2 O 2 via atomic regulation 1D Covalent Organic Frameworks

Abstract

Photocatalytic oxygen reduction reaction (ORR) and water oxidation reaction (WOR) are highly promising green methods for hydrogen peroxide (H₂O₂) production. However, designing efficient photocatalysts for H₂O₂ synthesis remains a significant challenge. In this study, a series of novel one-dimensional covalent organic frameworks (1D COFs) named as FZU-301 (-S-), FZU-302 (-O-), FZU-303 (-CH2-) with typical 4-c sql topology were synthesized by precisely modulating edge linkers. The research revealed that the electronic structure and charge transfer properties of the 1D COFs were significantly influenced by the edge linkers. Among them, FZU-303 with an all‑carbon‑bridging structure exhibits a lower exciton binding energy (Eb = 33.4 meV) than most reported COFs, along with the high carrier density, superior charge separation, and excellent charge transfer efficiency. Under sacrificial-agent-free conditions, FZU-303 demonstrated outstanding H₂O₂ production performance via three possible pathways: O₂→•O₂⁻→H₂O₂, O₂→•O₂⁻→1O2 →H₂O₂, H2O→H2O2. Its H₂O₂ yield reached 4642 μmol g⁻¹ h⁻¹, with solar-to-chemical energy (SCC) efficiency of 0.95%, surpassing most reported photocatalysts for H₂O₂ production. Moreover, after 12 hours of continuous photocatalytic reaction, a 4.4 mM H₂O₂ solution was obtained, which could be directly used for purifying wastewater contaminated with dyes and phenol.