One-Pot Solvothermal Synthesis of Graphene Nanocomposites for Catalytic Conversion of Cellulose to Ethylene Glycol

Three nanocomposite catalysts such as Ru/graphene, WO 3 /graphene, and Ru–W 18 O 49 /graphene were synthesized by solvothermolysis to increase the ethylene glycol (EG) yield from the hydrothermal conversion of cellulose. The morphology and composition of the nanocomposites were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller, scanning electron microscopy, and transmission electron microscopy. The results showed a new nanocomposite made up of graphene nanosheets that supported in situ growth of Ru nanoparticles with an average size of ∼7 nm and W 18 O 49 nanowires with an average diameter of ∼5 nm. Compared to Ru/graphene and WO 3 /graphene nanocomposites, Ru–W 18 O 49 /graphene showed nearly unit conversion of cellulose at a yield of 62.5% of EG when the reaction was carried out at 245 °C for 60 min. Moreover, it could be used at least three times with the high yield of EG in the range of 48.7–62.5%; however, with the increase of recycled runs, the tungsten species on the surface of graphene would be slowly dissolved in the aqueous solution and then the selectivity of this catalyst would gradually decrease. Besides, the one-pot solvothermal synthesis enabled reduction of Ru ions, graphene oxide, and growth of W 18 O 49 nanowires to thus provide a simple approach for the preparation of the graphene-based nanocomposite catalysts.