Furfuryl Alcohol-Driven Proton Supply Enables Efficient Photocatalytic H₂O₂ Production Beyond Water-Based Systems

Photocatalytic H₂O₂ production via the two-electron oxygen reduction reaction is often limited by rapid charge recombination and insufficient proton supply in aqueous systems. Here, we construct a covalently linked ZnIn₂S₄-carbon dots (ZIS-CDs) develop a coupled system that integrates H₂O₂ generation with selective oxidation of furfuryl alcohol (FFA). The built-in electric field in the ZIS-CDs heterojunction enables efficient charge separation. FFA acts simultaneously as a sacrificial electron donor, oxidation substrate, and proton source in the ultra-dry acetonitrile (ACN)-FFA system. During its oxidation, FFA supplies protons for H₂O₂ generation and is selectively converted into furoic acid (FA). This dual regulation of charge transfer and proton supply leads to an H₂O₂ production rate of 24 mmol·g^{- 1}·h^{- 1}, an apparent quantum yield of 14.57% at 400 nm, and a solar-to-chemical conversion efficiency of 1.78%, with 100% selectivity and 98% conversion to furoic acid. This work introduces a new strategy that couples organic transformation with proton management to enhance photocatalytic H₂O₂ synthesis.