Preparation And Catalytic Performance Of Ag/SiO₂Composite Hollow Sphere

In recent years, multi-functional composite materials with specific structures andphysico-chemical properties have become a research hotspot in many areas. Particularlyorganic polymers of Polystyrene (PS) spheres and inorganic hybrid materials of silica, hollowcomposite materials supported noble metal nanoparticles have a greater concern. Because rawmaterials of these materials are cheap and easily to get. These materials have manyproperties, for example, simple and convenient preparation, low toxicity, low density, highspecific surface area and good biocompatibility. These materials can be used for separation ofhydrophobic material, biological and drug delivery. Their application of catalysis has also gotmore and more attention.Firstly, this text has prepared PS spheres of different diameters by dispersionpolymerization and emulsion polymerization. And PS spheres were modified by carboxyl andamino sulfonic acid traditionally. Then we use ethyl orthosilicate (TEOS) as a reaction of theprecursor and silicon source. PS microspheres of1.2m synthesized by dispersionpolymerization of are as templates, and PS/SiO2composite materials with strawberrystructure simply were synthesized by sol-gel method and one step. Experiments results showthat we can regulate the reaction parameters of polyvinyl pyrrolidone (PVP), TEOS andammonia, and PS/SiO2composite materials with different strawberry structures can be got. Inaddition, this text did the systematic characterization for these different factors affecting theresults.Secondly, the text synthesized carboxy-polystyrene (PS-COOH) spheres of about450nmby emulsion polymerization, taking PS-COOH) spheres as templates, and successfullyprepared Ag/SiO2composite hollow spheres using one-pot method, using TEOS as siliconsource, methyl hydrogen polysiloxane (PMHS) as a reducing agent and a porogen agent.And the systematic characterization results of composite hollow spheres indicate that themesoporous materials have a large specific surface area, more evenly distributed silvernanoparticles and complete spherical shell structure. Moreover, the experiment proved that this composite hollow sphere has catalytic properties for the reduction of p-nitrophenol intop-aminophenol.The systematic characterization and performance testing results of composite materialsindicated that PS/SiO2composite materials with strawberry structure can be used as ahydrophobic material and carrier, and Ag/SiO2composite hollow spheres will also have avery good prospect in catalysis and separation science.