Regulation of Redox Molecular Junctions in Covalent Organic Frameworks for H₂O₂ Photosynthesis Coupled with Biomass Valorization

Abstract

H₂ O₂ photosynthesis coupled with biomass valorization can not only maximize the energy utilization but also realize the production of value-added products. Here, a series of COFs (i.e. Cu₃ -BT-COF, Cu₃ -pT-COF and TFP-BT-COF) with regulated redox molecular junctions have been prepared to study H₂ O₂ photosynthesis coupled with furfuryl alcohol (FFA) photo-oxidation to furoic acid (FA). The FA generation efficiency of Cu₃ -BT-COF was found to be 575 mM g^-1 (conversion ≈100 % and selectivity >99 %) and the H₂ O₂ production rate can reach up to 187 000 μM g^-1 , which is much higher than Cu₃ -pT-COF, TFP-BT-COF and its monomers. As shown by theoretical calculations, the covalent coupling of the Cu cluster and the thiazole group can promote charge transfer, substrate activation and FFA dehydrogenation, thus boosting both the kinetics of H₂ O₂ production and FFA photo-oxidation to increase the efficiency. This is the first report about COFs for H₂ O₂ photosynthesis coupled with biomass valorization, which might facilitate the exploration of porous-crystalline catalysts in this field.