Preparation Of Grephene Based Oxide And The Research Of Its Photocatalytic Performance

Photocatalysis is a new green technology,which was widely used in energy and environmentfield because of its soft reaction conditions,no secondary pollution and Simple equipment.Reduction carbon dioxide?CO₂?by photocatalytic process can solve the energy and environment problems in a certain extent The small specific surface area,fast recombination rate of the electron-hole pair and the low quantum efficiency of single catalyst was disadvantageous for the photocatalytic process.Graphene based semiconductor nanomaterials,which was combine graphene and semiconductor,can improve the specific surface area,restrain the recombination rate of electron-hole pair and activated CO₂ to enhance its photocatalytic efficiency on reduction of CO₂.TiO₂ CuO and NiO was the common semiconductor oxide which possessed the advantage of low cost and simple preparation.We prepared graphite oxide?GO?by modified Hummers method firstly and then combined with TiO₂ CuO and NiO by a simple hydrothermal?solvothermal?method.We prepared a series of graphene-oxide compound by control the amount of GO,and investigate its photocatalytic ability on reduction of CO₂ under the simulativevisible light.The main contents are as follows:1.The Ag-TiO₂/r-GO with different ratio of graphene was prepared by a simple hydrothermal method.X-ray diffraction?XRD?,Transmission Electron Microscopy?TEM?,High Resolution Electron Microscopy?HR-TEM?,Fourier Transform Infrared Spectrum?FT-IR?,UV-Vis diffuse reflectance?UV-Vis DRS?,Nitrogen Adsorption-Stripping Analysis and Photoluminescence?PL?was used to character the prepared samples.The results demonstrated that the GO was prepared by modified Hummers method successfully,the Ag-TiO₂nano-particles was disperse on the surface of graphene uniformly.The scope of lightabsorption was broaden and the recombination of electron-hole pair was restrain with the introduced the graphene.The photocatalysis results demonstrated that the activity of compound was much higher than single TiO₂ on the reduction of CO₂.The ratio of r-GO and the concentration of catalyst was the important for the reduction of CO₂.The catalyst possessed the highest activity when the ratio of r-GO was 15% and the concentration of catalyst was 1.5 g·L-1.The yield of methanol was 40 ?mol·gcat-1 on the optimumcondition.The cycle experiment demonstrated that the compound had a better photostability.2.The CuO nano-particles was prepared by a direct precipitation method and then modified by a APTES.The CuO-r-GO with different r-GO raito was prepared by a simple hydrothermal method.XRD,TEM,FT-IR,UV-Vis DRS and PL was used to character the prepared samples.The results demonstrated that the CuO nano-particlesadhere to the r-GO surface successfully,the ratio of the recombination of electron-hole pair was decline.The single CuO did not possessed the ability of reduction because of its low redox potential according to the photocatalytic results.The photocatalytic ability of reduction CO₂ was much higher when introduced the r-GO.3.We used the hydrothermal process to prepared the carbon spheres,and then the hollow NiO nanospheres was prepared by a carbon spheres template with a hydrothermal-sintering method.We used the GO and hollow NiO nanospheres to prepared the NiO-r-GO nanocomposites.XRD,TEM,FT-IR,UV-Vis DRS and PL was used to character the prepared samples.The results demonstrated that the partical size of hollow NiO nanospheres was uniform,and they attached to r-GO evenly.The single NiO nanospheres had a poor ability to reduction of CO₂ under the visible light because of its wide band gap width.The photocatalytic activity of the composite was much higher when introduced the r-GO.