Porous Zirconia And Titanium Oxides With High Surface Areas:Preparation,Characterization,and Photocatalytic Performance

Photo(electro)chemical processes plays an important role in solar-driven photocatalytic activities, regeneration energy(such as Dye-sensitized solar cells, DSSCs). To obtain highly efficient photo(electro)chemical processes semiconductor, several requirements should be satisfied. First, strong absorption to UV-visible region; Secondly, excellent electron transfer effectiveness; Third, highly surface area and light scattering, those properties should lead to highly efficient of surface adsorption and reaction. Transition metal oxides are the series of oxide semiconductor materials can be used as photocatalysis or photoanode, have attracted extensive interest in photocatalysis, DSSCs and etc. Transition metal oxide material with high refractive index, it is suitable for preparation of three dimensionally ordered macroporous (3DOM) materials. In this thesis focuses on characteristics of three-dimensional ordered macroporous structure and its pore wall, and the conditions that influence ordering of3DOM. And testing the TiOx sample, which is obtain from the high temperature hydrogen reduction of3DOM TiO2, photocatalytic activities.With the micro emulsion polymerization method and Stober method respectively, we prepared380nm,470nm PMMA microspheres and273nm SiO2microspheres, and standard deviations were31.15,24.39and12.21, respectively. Assembling template by room temperature floating self-assembly method, centrifugal method, gravity method, spin coating method and the vertical deposition method. Using scanning electron microscopy (SEM) investigate template morphology.TiO2and ZrO2three-dimensional ordered macroporous(3DOM) materials were prepared by infiltrating TiO2sol synthesized by sol-gel process and ZrOCl2·8H2O solution into the polystyrene (PS) colloidal crystal templates, respectively, and then by heating treatment. The characteristics of walls of ordered macrospores are closely related to the performance of3DOM materials in applications. The characteristics of pores walls of3DOM materials such as the microscopic structure and chemical composition were investigated by scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive spectrometry (EDS), and infrared spectra (IR). Results show that the pore structure of3DOM can be tuned by using different heating temperature and different size of PS spheres. We also focuses on the investigation of surface characteristics of pore wall of3DOM.Enhancing highly surface area material at high temperature is a great challenge due to sintering makes materials densification and agglomeration. Here we report a successful synthesis of high surface area TiOx by multistep template-assisted route.In this thesis, the specific surface area of this TiOx approach38.5m2/g. The preparation approach involves three stages, colloidal crystal templates were assembled by centrifugation method, which is followed by soaked in TiO2sol. Then the samples were calcined in air to burn away the template. Finally, moved the sample in hydrogen environment obtained porous TiOx. This porous TiOx only reflection～10%total solar wave by improving visible absorption, superior to P25(～77%), when the wavelength larger than400nm. The sample degraded71%of methylene blue after1h. It is expected that such kind of porous TiOx materials should have potential applications in the field of photocatalysis applications.