Synthesis of g-C3N4/TiO2/RGO Ternary Composites and Performance for Catalytic Fructose Dehydration to 5-Hydroxymethylfurfural

Abstract

A novel ternary composites of g-C3N4/TiO2/RGO were revealed by hydrothermal route and applied for the production of 5-hydroxymethylfurfural via dehydration of fructose. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and Brunner Emmett teller were used to characterize the morphology crystal form, groups and specific surface areas of g-C3N4/TiO2/RGO ternary composites. The key factors of reaction time, reaction temperature, solvents and catalyst mass ratios for fructose conversion and selectivity and productivity of 5-hydroxymethylfurfural were systematically screened, so were the catalyst’s stability. Experimental results indicated that the g-C3N4/TiO2/RGO ternary composites has good catalytic activity and stability with its’ complex three-dimensional network structures, affording the specific surface area up to 31.4782 m2/g. An excellent fructose conversion of 98.5% was achieved with optimal reaction condition of the fructose mass 0.5 g, dimethyl sulfoxide 15 mL, g-C3N4/TiO2/RGO dosage 1.0 g, reaction time 3 h and reaction temperature 150 °C, furnishing a good yield and selectivity of 5-hydroxymethylfurfural of 69.7% and 70.8%, respectively. Furthermore, the yield of 5-hydroxymethylfurfural can still reached 58.8% after five cycles of reusage of the catalyst.