With The Preparation Of The Special Morphology Of The Metal Sulfide Nanomaterials

In this dissertation, polyethylene glycol (PEG) was used as a structure-directing agent to prepare Ag₂S and CdS hollow spheres, PbS and Ag nanorods. Also, cetyltrimethylammonium bromide (CTAB) was used as a structure-directing agent to prepare novel nest-shaped Co hollow spheres. These nanostructures were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction(XRD),UV-vis spectroscopy, Fourier transform infrared(FT-IR) spectrometer, fluorescence spectrophotometer. In addition, electrogenerated chemiluminescence (ECL) curves of the CdS nanocrystal were measured by an electrochemical working station. The magnetization hysteresis loops of the magnetic nanostructures of Co were measured with a vibration sample magnetometer(VSM). The main results were as follows:1. Hollow Ag₂S spheres had been prepared via hydrolyze reaction of Ag₂S₂O₃, which formed from the reaction of AgNO₃ with Na₂S₂O₃, in cyclohexane/water/polyglycol emulsion system. It was found that the component of the reaction system has a significant influence on the formation of hollow Ag₂S spheres. The possible formation mechanism of the hollow Ag₂S spheres in the emusion system was discussed.2. PbS nanorods with the diameter in the range of 20 — 50 nm had been prepared in the polyglycol solution. On the basis of the HRTEM analysis, it was found that the PbS nanorods were single crystal and encapsulated in polyglycol. The wall thickness of the polyglycol was about 6 nm. Such a composite nanostructure could enhance the chemical stability of the PbS. It is confirmed by using (FT-IR) spectrometer that the affinity of the oxygen atoms in PEG chains for Pb²⁺ exists in the PEG-Pb²⁺ solution. The possible formation mechanism of the PbS nanorods in the polyglycol solution was also discussed.3. Hollow CdS spheres with the diameters in the range of 10 40 nm and thewall thickness about 10 nm had been prepared in the polyglycol solution. Compared with previous reports, the present method is very simple and rapid with the yield of hollow spheres up to 90%. The UV-Vis absorption spectrum (a peak at 470 nm) and photoluminescence spectra (a peak at 420 nm) of the hollow CdS spheres were blue-shifted considerly relative to the bulk CdS because of the quantum size effect. Electrogenerated chemiluminescence (ECL) curves of the CdS nanocrystal indicated a novel application of CdS-PIGE (paraffin-impregnated graphite electrode) in chemosensing in aqueous solutions.4. Using PEG as template, dentritic and ricelike Ag nanostructures were obtained by using diamide hydrate to reduce different concentrations of AgNC?3 solution. While only using polyglyol as reducer to reduce AgNC>3, Ag nanorods composed of nanoparticles was generated. The reaction processes of Ag nanoparticles with different shapes can be tracked by UV-vis absorption spectrum in polyglyol solution. The experimental shows that, as the reaction went on, the plasmo nabsorption peaks of Ag nanoparticles changed from single to multiplicity.5. Nest-shaped Co hollow spheres was prepared by the reduction of CoSO4 by NaBRt in CTAB/cyclohexane/water emulsion and the magnetic properties of the nanostructures were also measured. To the best of our knowledge, this new type of nanostructure has not been reported previously.