| Summary: | 碩士 === 明志科技大學 === 化工與材料工程研究所 === 96 === TiO2 has been widely used as photocatalyst. The photocatalytic reaction of TiO2 can be activated under UV irradiation. The TiO2 photocatalytic activity was low because it can’t absorb the visible light. In this study, the modification effects of TiO2 photocatalysts by two methods were investigated. And comparing the photocatalytic activity between two methods was discussed.
For the surface modification of the TiO2, the TiO2-Ag core-shell nano-particles were prepared via one-pot method in the first part of experiments. The silver shell acts the roll of trapping electrons to enhance the photocatalytic activity. On the other hand, TiO2 particles were bulk modified by solid-state-reaction methods; doping TiO2 with oxide dopants to induce oxygen vacancies and then decreasing its energy gap to enhance the photocatalytic activity.
The absorption intensity of TiO2-Ag particles prepared for 1.5 hours of hydrolysis is stronger than that for 2.5 hours of hydrolysis. The absorption intenity of TiO2-Ag particles is decreases as much more water added for the hydrolysis reaction.
For the modification of TiO2 by solid state reaction methods, the solubility decreases with increasing the difference in cationic charge and size between dopants and matrix. Dopants SnO2 and Nb2O5 have the best effect in enhancing the absorption intensity of TiO2.
Dopant Li2O reacts with TiO2, possibly because of its low solubility.
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