Preparation, Photo-and Electrocatalytic Properties Of Iron, Colbat And Nickel Nano-Oxides And Nano-composite Oxides

Iron, cobalt and nickel oxides and composite oxides are widely applied in magnetic materials, catalyst, sensor materials, cell, and so on. It is significant to explore novel synthesis methods and expond the application extents of iron and cobalt and nickel composite oxides. The main contents can be summarized as follows:1.Individual iron, cobalt and nickel oxide with different morphologies were synthesized mainly using hydrothermal method. Under controlled conditions, Fe3O4 nanosheet, Fe2O3 nanoparticle, Co3O4 nano-sheet,-tube and -particle, as well as NiO nanosheet and empty sphere, were prepared successfully respectively. Using a cyclic voltammetry method, the electocatalytic property of the as-synthesized oxide modified on a glassy carbon electrode (GCE) for the reduction of p-nitrophenol existing in a basic medium were investigated. The results indicate that Fe3O4 nanosheet, Co3O4 nano-tube and -particle, and NiO empty sphere all exhibit higher electrocatalytic activity. Under irradiation of visible light, the photocatalytic property of methyl orange degradation by oxidation of oxydol using the as-prepred oxides as photocatalysts with different morphologies were investigated, which are indicative of a certain potocatalytic activity for methyl orange degradation.2.Ag/Fe3O4 nano-sphere and-particle, sphere-like Cu/Fe3O4, and CuO/Fe2O3 composite nanostructres with different Cu/Co molar ratios, were fabricated. Via a cyclic voltammetry method, the electrocatalytic property of the as-synthesized samples decorated on a GCE for p-nitrophenol reduction in a basic solution were investigated. By comparison with a bare GCE,p-nitrophenol reduction is carried out with a magnified peak current using these as-prepared composite samples as catalysts. Under irradiation of visible light, CuO/Fe2O3 composites with different Cu/Fe molar ratios were used as the photocatalysts for degradation of methyl orange and p-nitrophenol by oxidation of oxydol, and exhibited higher photocatalytic activity for metyl orange and p-nitrophenol degradation. 3.Sheet- and tube-like Ag/Co3O4 as well as low dimensional MO/Co3O4 (M=Cu, Ni, Zn and Cd) composite oxides were synthesized via an facile and easy-controlled method. Through the analysis with XRD diffraction, the M-Co (M=Cu, Ni and Zn) composte oxides with M/Co molar ratio of 1:2 demonstrate a spinel structure of Co3O4 but Cd-Co one with the same molar ratio is verified as hybrid oxides using (NH4)2C2O4 as precipitation reagent. The electrocatalytic property of the as-prepared products for p-nitrophenol reduction in a basic solution was investigated. The results indicate that p-nitrophenol reduction could be carried out at lower potential under the catalysis of Ag-Co composites, and could be done with a large peak current with the Cu-Co ones, but M-Co (M=Ni, Zn and Cd) composite oxides show common or weak electrocatalytic activity for p-nitrophenol reduction. The photocatalytic property for methyl orange degradation with CuO/Co3O4 composites prepared via a precipitation method demonstrates that the samples with higher Cu/Co molar ratio exhibit higher photocatalytic activity.4. Ag/NiO nano-particle,-sheet and empty sphere, Au/NiO empty sphere, and CuO/NiO nanosheet, were synthesized using a hydrothermal/solvothermal metod. Using a cyclic voltammetry method, the electrocatalytic property of the M/NiO (M= Ag, Au) samples for p-nitrophenol reduction in a basic solution was investigated. The results show that p-nitrophenol can be reduced effectively at lower potential under the catalysis of the as-synthesized products. The photocatalytic property of CuO/NiO nanosheets for p-nitrophenol degradation by oxidation of oxydol under irradiation of visible light was examined. The results indicate that CuO/NiO composites oxide with higher Cu/Ni molar ratio exhibit higher photocatalytic activity.