Study On Synthesis And Properties Of Semiconductor And Noble Metal Nanoparticles

(1) Different generations of PAMAM were firstly synthesized and employed to stabilize noble mental nonaparticles (Au,Ag and Pt) in an aqueous-solution. The sizes of nonaparticles were effected by the generations of PAMAM dendrimers and the molar ratio of PAMAM to noble mental nonaparticles.(2) 1,8-naphthalimide-labelled polyamidoamine dendrimer (1GN) was synthesized and employed to stabilize Au and Ag nanoparticles. Compared with the first generations polyamidoamine dendrimer (1.0G PAMAM), Au and Ag nanoparticles protected by 1GN had smaller size and distributed more evenly. Owing to the chromophore of 1, 8-naphthalimide, Au and Ag nanoparticles were marked via fluorescence.(3) 1,8-naphthalimide-labelled polyamidoamine dendrimer (4GN) whose has good solubility in water and fluorescence character was synthesized and employed to stabilize Ag nanoparticles and design for ionic detection. The results have shown clearly that Ag nanoparticles could be effect the fluoresence intensity. Its ability to detect ions has been evaluated in an aqueous-solution by monitoring the quenching and enhancement of different metal ions have been tested: Cu²⁺ and Ce³⁺. In addition, it has been shown that for 4GN in an aqueous-solution, the fluoresence intensity is pH dependant, hence could find application as a detector of harmful pH changes in the environment.(4) CdS nanoparticles capped with PAMAM dendrimer have been prepared in an aqueous-solution. The sizes and fluorescence properties of CdS nanoparticles were effected by the generations of PAMAM dendrimers and the molar ratio of PAMAM to CdS.(5) Active carbon(AC) loaded magnetic photocatalyst, TiO₂-Fe₃O₄/AC, were prepared by sol-gel method. The photocatalytic activity was evaluated by degradation of methylene blue in aqueous solution under the irradiation of UV light. The results indicated that the magnetic photocatalyst(loading 20 % TiO₂ and 58 % AC)loading 22% Fe3O4 in mass ratio showed the highest photocatalytic activity ( The photo-degradation yield upon methylene blue after 2 h reached 87 %, being 2.7 times higher than that of pure TiO₂ ). The magnetic photocatalyst can be separated from the system and cycled utilization by applying magnetic field.