Design Of VO_x-RGO Hybrid Materials And Their Catalytic Performance Research

Graphene is a novel two-dimensional carbon material, it′s basic structure is the carbon atoms in sp2 hybridization to form a hexagonal cells and extend infinitely to honeycomb. Graphene has some unique properties like surperhigh specific surface area, transmit and receive molecules or atoms effectively, prominent thermal conductivity and mechanical property, eternal electric conductivity and ultrahigh electron mobility at room temperature, fractional quantum hall effect,quantum tunneling effect, and so on. These properties make it very suitable for as a carrier to develope composite materials with high performance.Vanadium is a transition metal, it has various chemical valence state and excellent catalytic property when it serves as a catalyst′ active component to catalyze oxidation reaction selectively. In this paper, we use hydrothermal method and microwave method to decorate mesoporous materials onto the surface of graphene, then modified it by vanadium oxides in order to prepare new graphene composites, then applied it for the epoxidation of styrene reaction. The main research content is as follows:1. Synthesis, characterization and photocatalytic activity of V-SBA-15-RGO compound in epoxidation of styrene. We use the improved Hummers method to prepare graphite oxide, ethyl orthosilicate as silicon source, P123 as template, use microwave method to synthesize SBA-15-RGO rapidly, then calcine it at high temperature in the tube furnace to prepare V-SBA-15-RGO composite. Using XRD,FT- IR, N2-isothermal adsorption desorption, SEM and TEM to characterize the catalysts, after loading metal vanadium, the characterization result demonstrates it hasn′t too much effect on mesoporous structure, the sample still maintain the mesporous structure. We discuss the effect of reaction time, the dosage of catalyst, the mole ratio of H2O2/Styrene, the dosage of hydrochloric acid, the mass fraction of metal in the reaction of epoxidation of styrene. The results shows 10%V-SBA-15-RGO composite catalyst has the best catalytic effect on styrene epoxidation experiment.The conversion rate of the epoxidation of styrene system canreach 46.34%, the selectivity of epoxy ethyl benzene is 19.11%.2. Synthesis, characterization and photocatalytic activity of VOx-RGO@mesoporous Ti O2 composite in epoxidation of styrene. In this work, we use the improved Hummers method to prepare graphite oxide, impregnation method is used to load the metal vanadium onto the graphene oxide. Then we use tetrabutyl titanate as titanium source and PEG-6000 as the template agent to synthesis VOx-RGO@mesoporous Ti O2 by hydrothermal method, finally calcine it at high temperature in the tube furnace. Using XRD, FT- IR, N2-isothermal adsorption desorption, SEM and TEM to characterize the catalysts, the characterization result demonstrates vanadium was loaded on the carrier successfully and the composite catalyst has mesoporous structure. We discuss the influence of reaction time, the dosage of catalyst, the mole ratio of H2O2/Styrene, the dosage of hydrochloric acid, the mass fraction of metal in epoxidation of styrene. The result shows the VOx-RGO@mesoporous Ti O2 composite catalyst has catalytic effect on styrene epoxidation experiment.