Vanadium-oxo immobilized onto Schiff base modified graphene oxide for efficient catalytic oxidation of 5-hydroxymethylfurfural and furfural into maleic anhydride

Graphene oxide (GO) sheets are emerging as a new class of carbocatalyst, and also a perfect platform for molecular engineering. The hydroxyl groups on either side of GO sheets can function as anchors by employing them as scaffolds linking organometallic nodes and vanadium-oxo was homogeneously immobilized on a Schiff base modified GO support via covalent bonding. The developed VO-NH2-GO was shown to be an efficient and recyclable heterogeneous catalyst for the aerobic oxidation of 5hydroxymethylfurfural (HMF) into maleic anhydride. Up to 95.3% yield of maleic anhydride from HMF and 62.4% from furfural were achieved under optimized reaction conditions. The immobilized vanadium oxo was identified as the active sites, while the residual oxygen-containing groups worked synergistically to adsorb HMF to maintain a high reactant concentration around the catalyst. The STY value was enhanced significantly over VO-NH2-GO, compared with homogeneous or heterogeneous traditional supported V based catalyst.