Preparation And Photocatalytic Activity Of C Or Fe-doped TiO₂/glass Nanotube Array Films

This thesis has briefly described the new photocatalysts and photocatalyticmechanism, and has given an overview of the current progress and suffered problemsabout the optimization of TiO₂photocatalyts by doping, modification, andsensitization upon visible light. Then, the thesis, titled “Preparation and photocatalyticactivity of C or Fe-doped TiO₂/glass nanotube array films”, mainly focuses on thefabrication of Carbon-doped and Fe-doped TiO₂nanotube ordered array films andtheir photocatalytic activity. The corresponding works and results were shown asfollowing:1. Highly ordered TiO₂nanotube arrays （TNAs） were synthesized by anodizationof Ti foils. Followed by an annealing treatment in acetylene atmosphere, transfer, andadhesion of TNA membranes, then the crystalline C-doped TiO₂nanotube arrays（C-TNAs） on glass were fabricated. The as-prepared samples were characterized indetail by scanning electron microscopy, X-ray diffraction, X-ray photoelectronspectroscopy, UV-VIS transmittance spectroscopy, and photoluminescencemeasurement. And their photocatalytic activities were also investigated in thephotocatalytic degradation of methyl orange. The results indicate that, after carbondoping, the absorption range of TNAs was enlarged to the visible region, and thephotocatalytic activities were significantly enhanced. Furthermore, the absorptionedge of C-TNAs showed a red shift and the photocatalytic activities werecontinuously improved with the increasing of the annealing temperature. When theannealing temperature was550°C, the optimized photocatalytic activities weregained, and the apparent reaction rate constant of C-doped （k,0.065min-1） was3.6times that of pure TiO₂（k,0.018min-1）. More importantly, the resultant film had anexcellent stability in the reuse processes.2. Porous Fe-doped TiO₂thin films were prepared on the glass by spin coating ofthe TiO₂sol including the polyethylene glycol2000（PEG2000） and Fe ions. Themorphology, crystalline structure, and optical properties of the as-grown specimenswere characterized by using of the Field-emission scanning spectroscopy, X-ray diffraction, UV-VIS transmittance spectroscopy, and photoluminescence （PL）measurement, respectively. It is found that the Fe-doped TiO₂thin films exhibitedporous structure with well-distributed pores, a red shift of the absorption edgeoccurred with the increase of Fe-doped concentration. And the maximum red shiftwas150nm as the concentration of Fe is0.15M, indicating that the Fe doping couldreduce the band-gap of TiO₂. Additionally, the recombination rates of the excitationwere heavily dependant on the doping concentration of Fe, for instant, thephotoluminescence signal of the Fe-doped TiO₂thin films firstly decreases and thenincreases with the increasing of doping, and reaches its minimum in0.10M.Obviously, the optimized parameter is benefit to improve the photoelectricperformances of porous TiO₂thin films.