Recent advances in the photocatalytic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

2,5-Diformylfuran (DFF) is one of the products of selective oxidation of 5-hydroxymethylfurfural (HMF), an important furan platform compound, and a new energy chemical, which is currently attracting much attention. Solar energy is considered to be a sustainable, clean, cheap, and green energy source. DFF synthesized by photocatalytic selective oxidation of HMF has the advantages of mild reaction conditions, easy separation of catalyst and product, green, and environmental protection, which has gradually become a research hotspot. This paper reviews the research progress in the catalytic conversion of HMF to DFF by photocatalytic oxidation in recent years, in particular the mechanisms of photocatalytic conversions of HMF are summarized, and different photocatalytic systems for photocatalytic oxidation of HMF are classified and summarized in detail, with emphasis on the selectivity of DFF. We hope that the present review will provide a great foundation and guideline for future studies of biomass cleaner valorization.