Characterization And Application Of Transition Metal Ion-doped Mesoporous TiO₂ Materials

Mesoporous TiO₂ materials which because of their photocatalytic, catalyst carrier, sensors, electrochemical devices, and other aspects of the potential uses,are concerned recently, has become a new research direction on Materials science.It shows better photocatalytic efficiency than nano-particle TiO₂ in the degration of organic waste water,and shows broad application prospects in particular cases.First applied Gemini1231 as template in this experiment, samples were synthesized by sol-gel method at room temperature and characterized by differential thermal analysis, X-ray, N2 adsorption-desorption, degradation experiments. The results showed that when the titanium source and template ratio of 0.75, had better mesoporous structure, and specific surface area was up to 383.8m²/g, the size of the most pores was about 5.4 nm in diameter,the grain size was 22.60 nm. The strong anatase characteristic peaks was found in XRD spectra but the rutile phase diffraction peaks was not found.It proved that the preparation of mesoporous TiO₂ at this experiment was stability anatase. Small-angle X-ray diffraction analysis showed that the samples were regular mesoporous structure.However,the excitation can be used is limited to UV light. UV ligh is only about 4% of the sun light, which is far less reach the requirement in degration of various waste water.Transition metal ion doping in TiO₂ can introduce defects position or change crystallinity, thus affecting electron and hole recombination.The scope of optical absorption wavelength can be expanded by incorporating certain metal ions.So Fe³⁺ and V⁵⁺ were doped in this experiment thereby enhancing the catalytic activity of mesoporous TiO₂.Test results showed that the appropriate Fe³⁺ and V⁵⁺ doping did a little effect in mesoporous structure, but the photocatalytic activity of mesoporous TiO₂ was improved substantially.At last,the best ratio was found Through the experiment of photocatalytic degradation of methylorange.