| In this thesis, based on the advanced synthesis technique of Ag and TiO2 nanocrystal in our group, using photo-inducing method, we carried out the research on Ag/AgCl composite and Ag/TiO2 heterojunctions, combined silver nanocrystals with AgCl and TiO2 nanocrystals, obtained ideal Ag/TiO2 heterojunctions with intense intercoupling effect, and characterized the photocatalytic activity.Firstly, we prepared Ag/AgCl composite through photo-inducing method in a new microemulsion system which was represented firstly. The effects of concentrations of various reactants on the particle size and morphology were investigated primarily. The catalytic activity under visible light of the composite was proved through the decomposition of methylene blue.Secondly, we successfully synthesized excellent Ag/TiO2 heterojunctions in non-aqueous phase using photo-induction method with TiO2 nanocrystals with two different shapes as substrate. The obtained Ag/TiO2 heterojunctions presented much higher photocatalytic activity than pure TiO2 nanocrystals. And we proposed the critical induction effects oleic acid played in the formation process of Ag/TiO2 heterojunctions, which established theoretical basis for the research in aqueous phase.Finally, we implemented the firenew attempted on the synthesis of TiO2 nanocrystals and Ag/TiO2 heterojunctions in aqueous phase. Through hydrolysis and dehydration process, we successfully obtained disperse anatase TiO2 with clean surface and different shapes. And excellent Ag/TiO2 heterojunctions were synthesized in aqueous phase using photo-reduction strategy with TiO2 nanorods also obtained in aqueous phase as substrate. The much higher photocatalytic activity of our sample than all published researches under both visible light and simulation sun light evidently demonstrated that Ag/TiO2 heterojunctions obtained in aqueous phase can be developed as efficient photocatalyst for the degradation of pollutants under sun light. |
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