Improve The Modified Method Of Nanometer Of Tio <sub> 2 </ Sub> Photocatalytic Properties Of Metal Exploration

In this paper, a series of Cu-TiO₂ and Sn-TiO₂ catalysts have been synthesized by sol-gel method and simple impregnation process. The obtained samples were characterized in detail via TG, XRD, DRS, SPS, XPS and EIS methods. The photocatalytic activity of metal-modified TiO₂ was studied by degrading the Rhodamine Bextra solution (RhB). Meanwhile, the effects of different metal content,calcination temperature,calcination time, impregnation time on the photocatalytic activity of samples were investigated.The Cu-TiO₂ photocatalysts was synthesized at the calcination temperature of 400℃for 4 hours. The results of copper-modified TiO₂ photocatalytic degradation RhB experiments indicate when the Cu concentration is not larger than 0.06%, oxygen vacancies and Cu2+ species could be the trap centres of the photoinduced electrons and effectively inhibit the recombination of the photoinduced electrons and holes consequently in the photocatalytic process, which is favor to the increase of the photocatalytic activity for samples. However, when copper dopant content exceeds 0.06%, excessive oxygen vacancies and Cu2+ species could be the recombination of the photoinduced electrons and holes. At the same time, the excessive copper dopant content could also influence the efficient absorption area of samples and furtherly decreases the photocatalytic activity.The experimental results indicate that the photocatalytic activity of Sn-modified TiO₂ has been significantly enhanced. Firstly, that is because of the existence of Ti3+ ions, which could elevate the level of Femi energy and increase the number of hydroxyl radicals. Secondly, the density of oxygen vacancies is increased, which can effectively trap photoinduced electrons and inhibit the recombination of the photoinduced carriers. Thirdly, Sn species were absorbed on the surface of TiO₂ as Sn4+, which can also trap photoinduced electrons and inhibit the recombination of the photoinduced carriers. At last, Sn-modified TiO₂ introduce the dopping energy level of Ti3+, Sn4+, oxygen vacancies and hydroxyl radicals, which could produce the sub-band gap transition of catalysts, the doped energy level simultaneously participate in the photochemistry process, which make the photocatalysts can absorb the light whose energy is less than the Eg, which consequently expand the absorption range of photocatalyst to visible region. Furthermore,The paramagnetic ions of Ti3+ could accelerate the rate of intersystem crossing from singlet state to triplet state, excitors deactivate by radiativing phosphorescence, which inhibit the recombination of the photoinduced electrons and holes and then prolong the lifetime of photoinduced holes.