Under The Catalysis Of Silver Doped Alkali Titanium Dioxide Composite Powder Preparation And Performance Characterization

The research of semiconductor optical nanomaterials is wider and wider in recent years. People gradually begin to research semiconductor materials since titanium dioxide was used as electrode in water photo degradation by Fujishima and Honda in1972. With high photo catalysis, stability, low cost, non-toxic and other aspects of the advantage, semiconductor of titanium dioxide becomes the most potential application value of one of semiconductor materials in21st century. However, nanometer titanium dioxide itself has two limitations, one is the larger forbidden band width (more over3.2eV), and the low spectral responsibility and absorption ability in visible region, these negative factors limit the light catalytic performance itself in visible region. The other is, there is no enough time for the reactants to combine with electronic-hole in light of catalysis, which makes light quantum efficiency low down in photo catalysis of titanium dioxide. Therefore, to improve the corresponding region in the visible spectrum of bandwidth, the efficiency of titanium dioxide photo catalysis has become the major work for researchers. We always use non-metallic doping, metal doping, precious metals deposits, and photosensitive of dyes to control crystal growth.In current work, the sol-gel process was used to prepare the samples with Ti(OC4H9) and silver nitrate. C2H5OH as solvent, through controlling the mixture of the PH value, the reaction solution temperature, stirring speed and mixed silver content. Secondly, we uses APS to modify the surface compound light catalyst preparation. Thirdly, conditions of the reaction were in normal pressure and temperature which reduces the activation energy of products.The titanium dioxide powders were prepared via modified sol-gel method. The red shift of energy and the optical band gap is obtained by addition of Ag. The phase structure, microstructure and photocatalytic properties were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, fourier spectral absorption, differential thermal analysis, nanoparticle size analyzer, ultraviolet and visible spectrum photometer. The principal experiment results were shown as follows:Firstly, in hydrolysis reaction, TiO2gelling rate has great influence on the PH value of reaction solution, it is found that the potential of hydrogen in three to ten range which have better catalytic in light catalyst, strong acid or alkaline are against regularly growth of colloid solution, in the acidic conditions the nucleation rate faster, easily happened reunion phenomenon, unfavorable the light of the catalyst absorption efficiency, and in alkaline environment, hydrolysis into nuclear rate slower and more regular.Secondly, by difference of sliver contents, there has a great influence on the grain size, and enhanced the visible region of the absorption efficiency obviously. However, too much silver particles may lead to colloid inactivation and produce secondary reunion. Required amount of powders with Ag-TiO2weight ratio of1:20, maximum absorption catalyst light intensity was perfectly realized.Finally, with the appended surface modifier, the phase transition temperatures were restrained, and improved the catalytic properties effectively. The results showed that, the efficiency of the catalyst quantum was improved with a suitable content of modifier. However, excessive content of modifier may lead to aggregation. Moreover, with the APS=0.3modification of Ag/TiO2, showed the excellent performance of photo catalytic activity.