Synthesis And Property Investigation Of Noble Metal Monodisperse Nanocrystals And Low-Dimensional Chalcogenide Compounds

This dissertation is intended to develop the synthesis of noble metal monodisperse nanocrystals and chalcogenide compounds in functional nanomaterials respect. On the basis of the preliminary work, we summarized the insufficient contents of noble metal monodisperse nanocrystals and chalcogenide compounds in synthesis and application, and succeeded in preparation of noble metal monodisperse nanocrystals with both water-and oil-solubility, self-assembly CdTe nanowires and ultrathin monolayer Bi2Se3nanoflakes. The relevant properties characterizations were also performed. The details are summarized briefly as follows:1. A facile approach for the preparation of highly uniform and controllable noble metal nanoparticles, including Au, Ag, Pd, Pt, and their bimetals with different sizes in ethylene glycol at relative low temperature using oleylamine as a stabilizer was reported. The synthesized noble metal nanoparticles can be well dispersed in both water-and oil-based phases, and they are suitable for catalysis in both systems without any additional surface modifications. The detail mechanism of reaction and solubility of the nanoparticles was also elucidated.2. A new catalysis system was developed for the reductions of nitroaryl compounds using borane-tert-butylamine (BTB) as the hydrogen source instead of NaBH4. The new system of cyclohexane media different from the traditional NaBH4aqueous system can hydrogenate nitroaryl without influence of other reductive perssads, like carbonyl. Meanwhile, the new system performed an extremely high selectivity and conversion which were both up to99%.3. A novel multi-step self-assembly of CdTe nanowires and other morphologies of CdTe nanoparticles was designed and developed in oleylamine system with using CdCl2and diphenyl ditclluride as the precursor and adding tris(2-ethylhcxyl) phosphate as the surfactant. The as-synthesicd nanowires up to a maximum of20μ m, has good photoelectric properties for the visible light response, which can be very good for the fabrication of nanodevices 4. Based on the new Ullman reaction of the preparatory work, by further improving the reaction source, we synthesized ultrathin Bi2Se3nanoflakes of monolayer structure in oleylamine and oleic acid system with triphenyl bismuth and dibenzyl diselenide, and proved the monolayer structure of Bi2Se3by various characterizations.