Solvothermal Synthesis And Properties Of Rare Earth/Graphene Oxide Composites

It is well known that graphite oxide (GO) is a typical two-dimensional solid layer structure, Although there are many models describing the structure of graphite oxide, the exact structure of GO still remains unclear, there are plenty of functional groups on the surface structure, such as hydroxyl, carbonyl and other groups, these abundant functional groups between the layers of GO make them hydrophilic、excellent ability of ligand, provide good conditions which is coordinated with other materials.RexOy/RGO was successfully prepared by the reaction of rare earth chloride with graphite oxide in autoclave by solvothermal method. It was found that the composite has good catalytic activity in the oxidation of methylene blue by peroxide with the degradation which is based on good light absorption properties of graphite oxide. The main topics of this research are as follows:(1) The preparation of RexOy/RGO(Re=La/Ce) and its photo-catalytic activity in the oxidation of methylene blue by peroxide: The result shows that:Composites can be affected by the reaction time, the solvent ratio, reaction temperature, amount of metal oxide amount. It was found that RexOy/RGO obtained0.26gLa/gGO and0.28gCe/gGO in the mixed solvent (ethanol/carboxamide is2:1) and the reaction time of24h at100℃by adding0.5g graphite oxide and0.001mol Re. The obtained composites were investigated by different characterization methods, the result shows that graphite oxide was reduced to reduced graphite oxide in the solvothermal reaction process. The lanthanum oxide in the complexes was chemical bonding to reduced graphite oxide.It was found that the composites have good photo-catalytic activity in the oxidation of methylene blue by peroxide, the highest decolorization rate can reach99%, It was demonstrate that the photo-catalytic activity can promote through composing rare earth with graphite oxide.(2) Preparation, characterization and photo-catalytic of Eu2O3/RGO: The europium oxide crystals in composites are irregular with the solvent of ethanol/carboxamide, so ethanol was replaced by glycol, the crystals in materials becomes rule, and that grow into flower shaped. The composites were investigated by FT-IR and XPS, The result show that europium oxide in the complexes was chemical bonding to reduced graphene oxide, It was found that Eu2O3/RGO obtained has photo-catalytic activity in the oxidation of methylene blue by peroxide with the degradation rate of70%. (3) Preparation, characterization and photo-catalytic activity in the oxidation of methylene blue by peroxide of Re2O3/RGO(Re=Pr、Gd、 Tb):Re2O3/RGO was successfully prepared by the reaction of rare earth chloride with graphene oxide in a mixed solvent of ethanol-carboxamide in autoclave at100℃.the composites were investigated by SEM, the result shows that praseodymium oxide/RGO and gadolinium oxide/RGO morphology are flower-like structure, neodymium oxide/RGO and terbium oxide/RGO are crystalline particles.The photo-catalytic properties of Re2O3/RGO(Re=Pr、Gd、Nd、Tb): It was found that different catalysts have different catalytic performance, the result prove that the composites have strong photo-catalytic activity in the oxidation of methylene blue by peroxide, after reaction2h, the degradation rate can reach94%, which Pr2O3/RGO and Gd2O3/RGO is the best.