Simple synthesis of V2O5/g–C3N4 photocatalyst for the oxidation of biomass-derived 5-hydroxymethylfurfural

It is highly important to effectively convert 5-hydroxymethylfurfural (5-HMF) into the high-value chemical 2,5-diformylfuran (DFF). In this study, graphitic carbon nitride (g–C₃N₄) and V₂O₅ were combined to construct the V₂O₅/g–C₃N₄ composites by a simple calcination method. The composite catalysts were comprehensively and thoroughly characterized. Moreover, the factors affecting the photocatalytic performance of the composite catalysts were systematically investigated. Compared with pure g–C₃N₄, the introduction of V₂O₅ can accelerate the transfer of photo-excited electrons while simultaneously inhibit the recombination of photo-generated carriers. Furthermore, radical trapping experiments deduced that photo-generated holes, ·O₂⁻ and ¹O₂ are the primary active species for the reaction system. Additionally, electron paramagnetic resonance experiments further confirmed that more active species can be generated on the surface of the V₂O₅/g–C₃N₄ catalyst. Under the synergistic effect of many advantages, the V₂O₅/g–C₃N₄ photocatalyst displayed superior photocatalytic performance in the photocatalytic oxidation of 5-HMF, with the highest 5-HMF conversion of 66.7% and DFF selectivity of 65.4%. Combined with the characterization results and the energy band positions, it was postulated that the V₂O₅/g–C₃N₄ photocatalyst worked following a Z-scheme mechanism.