Selective valorization of 5-hydroxymethylfurfural to 2,5-diformylfuran using atmospheric O₂ and MAPBBr₃ perovskite under visible light

Selective production of value-added platform chemicals from renewable biomass feedstocks and their derivatives has attracted tremendous attention with high potential in addressing global problems of energy and sustainability. In this work, a lead-halide perovskite (MAPbBr₃, MA = methylammonium) is utilized as a photocatalyst for selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) using atmospheric O₂ upon visible-light irradiation. Under minimally optimized conditions, the photocatalytic conversion of HMF in acetonitrile solvent reaches 100% with a DFF selectivity of over 90%, achieving an overall furanic carbon yield of over 96%. A detailed catalytic mechanism was proposed based on various spectroscopic and experimental results, revealing that the atmospheric O₂, photogenerated electrons (e⁻), holes (h⁺), ^•O₂⁻, and ¹O₂ species together play crucial roles in the effective and selective photo-oxidation of HMF to DFF. In addition, our present photocatalytic system is also applicable for photo-oxidation of benzyl alcohol with approximately 100% conversion and benzaldehyde selectivity, providing insights for future exploration of the present catalytic system.