Modification Of Tio <sub> 2 </ Sub> Nanomaterials And Photocatalytic Performance Study

Deferent doping ratios Fe +-TiOa nano-material was prepared by sol-gel method and the effects on photocatalytic efficiency by using of Rhodamine B as evaluation standards were studied. The presence of Fe3+ ion significantly influences photoreactivity. Because we didn't find new phase from XRD and Raman spectroscopy analysis, the changes of photocatalytic activity were probably induced by the infiltration of Fe3+ ion into TiOi crystal lattice. From the Raman spectroscopy analysis, we found the changes of lattice constant for Fe3+ ion doping. There is an optimum-doping ratio, which can increase degradation ratio greatly. The main reason for the increase of degradation ratio is the hole trapping by Fe +, which decrease the recombination and increase lifetime of electron-hole. When doping ratio increase, the photoinduced electron and hole will meet more trapping which increase the chance of recombination. Compared with Fe3+ doping TiC>2 prepared by sol-gel method, it showed that TiC>2 prepared by hydrothermal method has the higher degradation ratio than sol-gel method, because it can prepared little size nano-particle with high specific surface.But using sol-gel method, we prepared different ratio Ag-TiOa nano-particles, and found when Ag content increase 3% and 5% the Rhodamine B would disappear nearly completely. From XRD spectroscopy analysis, we found silver particle existed on TiC>2 surface. From XPS and Raman analysis, we found there is some Ag+ ion that can be reduced to lattice Ag by Ti3+. The metal and the n-type titanium dioxide have different Fermi level positions. When the two materials connected electrically, electronmigration from the TiO2 conduction band to the metal occurs until the two Fermi levels are aligned. The bands of the TiO2 conduction band upward toward the surface, and the barrier formed at the metal Ag and T1O2 interface is called the Schottky barrier. It can serve as an efficient electron trap preventing electron-hole recombination in photocatalysis.In order to solve the problem of TiO2 power immobilization, the several types of TiO2-based materials were used such as silica gel, glass bead, and molecular sieve. The titanium dioxide film utilized the pore of silica gel to improve the adsorption for Rhodamine B so that the degradation ratio increased greatly than using TiO2 power. Moreover, by XPS, FTIR characterization, it showed that the bond of Ti-O-Si formed through high temperature calcinations. Through the bond, the electron can transfer from TiO2 to SiO2 that separate the photo-induced electron and hole.Rhodamine B was used as an objective degradation organic. We ascertained the proper conditions on reaction and provided better evidences that can be used to evaluate the photocatalyst' activity by researching the influence of physical parameters governing the kinetics, such as mass of catalyst, initial concentration of RhB, acidity of solution, temperature, and light lamp. ESI-MS and UV-VIS instrument were used for inspecting the reaction. There are two different degradation routes occurred in reactions, if TiO2 power were used as photocatalysis the ring of RhB would be opened and decomposed. If TiO2/SiO2 coating films were used, the de-ethyl reaction is distinctly observed as same as decomposition reaction.