Abstract:

Abstracr: The synergistic coupling of photocatalytic hydrogen peroxide (H₂O₂) production and green organic synthesis not only optimizes utilization of photogenerated electron-hole pairs but also circumvents kinetically sluggish water oxidation reaction. In this study, an efficient composite photocatalyst was developed through in-situ growth of irregular TpPa-Cl blocks on the surface of boron-doped TiO₂, which boasts a large specific surface area. Boron doping enhances light absorption range and inhibits recombination of charge carriers. Additionally, deep integration of porous TiO₂ with TpPa-Cl improves the contact between the reactants and the photocatalyst, extends the carrier lifetime, and provides more active sites. In the absence of a co-catalyst, the yield of H₂O₂ reached 2082.6 μmol g^-1 h^-1, with a furfuryl alcohol conversion rate of 94%. In-situ XPS and density functional theory calculations confirmed S-scheme charge transfer mechanism, which enhances carrier separation and transfer efficiency while retaining photogenerated electrons and holes with strong redox properties. Quenching experiments, electron paramagnetic resonance, and in-situ diffuse reflectance infrared Fourier transformed spectroscopy demonstrated that H₂O₂ was primarily generated via a 2-electron oxygen reduction reaction with ·O₂^- and OOH^* as intermediates. Furthermore, furfuryl alcohol was oxidized to the radical ·C₅H₅O₂ by h⁺ and subsequently converted to furfural or furoic acid through reactions with h⁺ or ·OH. This work presents a novel strategy for designing efficient composite photocatalysts for H₂O₂ production and green organic synthesis.

Key words: Photocatalytic H₂O₂ production, Porous structure, S-scheme heterojunction, Stability, Redox properties