Preparation Of Selenium Nanoparticles And Its Copper /Sliver Composites Through Intereface-growth Process

Nowadays, more and more nano-materials with excellent quality are demanded due to the rapid development of the science and technology. In order to obtain new nano-materials with good functions, the complex technology has often been applied. The complex technology can not only reduce the amount of expensive material, but also make the new materials more excellent than single material. The interfaces formed between different substances such as solid-gas, gas-liquid, liquid-solid, liquid-liquid, have particular structures and properties. The preparation of complex materials and nano-materials by interface-growth has attracted much attention. In this thesis, various nanoparticles with different morphologies, such as selenium, copper, sliver and the composites of selenium-copper, selenium-sliver, were prepared by liquid-liquid interface-growth process. The interface-growth mechanism of nanoparticles has been discussed and the photoelectric properties of the products have been determined.1. Preparation and characterization of Se nanoparticles: In water solution, SeO2 was first deoxidized into elemental Se by hydrazine monohydrate in the existence of surfactant. Then n-butanol was added into the reaction solution under stirring. Rod-like, sting-like and sphere-like Se nanostructures were obtained by the butanol-water interface-growth process. The effect factors such as temperature, the amount of reducing agent, ultrasound, surfactants were discussed. The products obtained were characterized with transmission electron microscopy(TEM), scanning electron microscopy (SEM) , thermogravimetry(TG) , differential scanning calorimetry (DSC), ultra-violet-visible (UV-Vis) and x-ray diffraction ( XRD) .2. Preparation and characterization of Cu nanoparticles: Cu nanoparticles were prepared through the reduction of CuSO4 by proper reducing agent inaqueous solution. Other conditions like the ones mentioned above. In order to avoid the oxidation of Cu in aqueous solution, sodium sulfite(Na2SO3) was used to get ride of the oxygen. Using polyvinylpyrrolidone (PVP) as the soft template. Cu nanoparticles with different morphologies, such as particle-like, rod-like, bolt-like, dendrite-like, flake-like, were obtained through liquid-liquid interface growth process. The products were characterized with TEM, SEM, UV-Vis and XRD.3. Preparation and characterization of Ag nanoparticles : Through the reaction of [Ag (NH3) 2]+ with mild reducer glucose, Ag nanoparticles with uniform sphericity, isosceles triangle, trapezium and hexagon, were prepared by liquid-liquid interface-growth process. The morphology, material phase and photoelectric property of the products have been studied.4. Preparation and characterization of Se-Ag and Se-Cu composites: The solution of Se(â…£)-Cu(â…¡) or Se(â…£)-Ag(â… ) was deoxidized with single reducing agent. Se nanoparticles could react with Cu nanoparticles producing CuSe nanoparticles because nanoparticles have higher activity than its bulk. The results of characterization have indicated that the products with different component were obtained in liquid-liquid interface by adjusting the proportion of Se and Cu or Ag. Interestingly, the nanoparticles with core/sphere and double layers were also obtained in the synthesis of Se-Ag complex.