Vanadium-embedded mesoporous carbon microspheres as effective catalysts for selective aerobic oxidation of 5-hydroxymethyl-2-furfural into 2, 5-diformylfuran

Vanadium dioxide (VO₂) embedded mesoporous carbon spheres (V-CS) were synthesized by a facile hydrothermal method followed by post thermal treatments in air. The V-CS materials were used as catalysts in the aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) using atmospheric oxygen as the oxidant. The effect of reaction time, temperature, catalyst loading and solvents on the reaction were investigated. Under optimized reaction conditions, a DFF yield of 99% can be achieved. The physical and chemical properties of the catalysts were studied by FESEM, BET, XRD, FTIR, Raman, XANES and element analysis. The characterization results evidenced that the micro/mesoporous structure of the carbon spheres along with the highly dispersed vanadium dioxide species is responsible for the excellent catalytic performance. The post thermal treatment was the key step to afford the superior V-CS catalysts successfully. In addition, the catalyst did not have any significant loss in activity during the recycling test, showing good reusability.