Study On Preparation And Functionalization Of Inorganic Hollow Nanospheres

Compared with solid spheres, Inorganic nano hollow spheres has low density, large surface area, hollow structure, high thermal stability, so it can be applied to chemical storage, photonic crystals, drug controlled release systems, catalysis as well as the fillers and the other fields. So far, it has been prepared by many different methods of hollow spheres of different materials, such as: carbon hollow spheres, metal spheres, ceramic spheres, hollow spheres of inorganic semiconductor nanoparticles, metal oxide hollow spheres and so on. But less research on composite hollow spheres and nano rare earth hollow spheres.In this paper, SiO₂,SiO₂/TiO₂,Y₂O₃ and CeO₂ hollow spheres were prepared by using nano polystyrene spheres as the template, basic on different taget substrate, sol-gel and calcining method. The synthesized products were characterized by Scanning electron microscopy (SEM), Transmission Electron Microscope (TEM), Fourier infrared spectroscopic analysis (FTIR) and X-ray Diffraction (XRD) etc. The main study results as follows:1. Using two-stage seeded emulsion mathod to prepare monodisperse polystyrene P(St-AA) microspheres, the obtained P(St-AA) spheres with a good monodisperse, particle size distribution was controllable, surface easy to functional, etc. The first phase of the seed particle size was approxmate 120nm, the second phase particle size is about 250nm.2. Used the P(St-AA) microspheres as the templates, TEOS as silicon resource, use the sol-gel method to prepare P(St-AA)/SiO₂ composite microspheres, then they were calcined at 550℃for 5h to removal the P(St-AA) template to form SiO₂ hollow spheres; Used P(St-AA)/SiO₂ composite microspheres as the template by sol-gel method to prepare P(St-AA)/SiO₂/TiO₂ composite microspheres, and then calcined at 550℃for 5h, then we get the SiO₂/TiO₂ composite hollow spheres. The various characterization results of SiO₂/TiO₂ composite hollow spheres showed that using the P(St-AA) as the template, sol-gel method to prepare SiO₂ hollow spheres and SiO₂/TiO₂ hollow spheres had good sphericity, smooth surface, relatively homogeneous particle size, SiO₂ hollow sphere particle size was about 280nm, shell thickness was about 20nm, SiO₂/TiO₂ hollow microsphere particle size was about 290nm, shell thickness was about 20nm, SiO₂/TiO₂ hollow spheres relative to the size of SiO₂ hollow spheres shrink slightly.3. Used yttrium nitrate hexahydrate as the yttrium resource, triethanolamine as precipitating agent,concentrated ammonia as the material to hydrolysis nitricyttrium, and (NH4)2SO4 as a surface modification agent, then were calcined at 900℃to removal P(St-AA) microspheres and successfully prepared Y₂O₃ hollow spheres. The particles size was about 100nm, the wall thickness was about 20nm. Used the Y₂O₃ hollow spheres composited with rubber polymer to prepare the Y₂O₃ hollow sphere/ rubber polymer composite material, and the obtened material have a very good property of low frequency sound absorption.4. The P(St-AA) as template-agent, cerium nitrate hexahydrate as the cerium resource, urea as precipitating agent and PVP as surface modification agent to prepare P(St-AA)/CeO₂ composite spheres. Then they were calcined at 600℃to removal P(St-AA) spheres were successfully prepared the CeO₂ hollow spheres. The CeO₂ hollow spheres were perfect with crystals, theirs size was about 250nm, the wall thickness was about 10nm. We use the CeO₂ hollow spheres to degrade simulation dye effluents with methylene blue with a good bleaching performance.