Preparation And Characterization Of Silver Nanoparticles Fabricated By APTES

Silver nanoparticle,one of important noble metal nanostructures,has attracted extensive attention due to their fascinating optical,electrical,magnetic properties and their great potential applications in surface-enhanced Raman scattering(SERS),biosensing,catalysis and antibiosis.These properties and applications are highly depended on their size,shape and ligands on the surface.Thus,control of the morphology is a primary focus.In this dissertation,we describe a simple method to prepare silver nanoparticles with different shapes regulated by using 3-aminopropyltriethoxysilane(APTES)at room temperature.SERS performance and catalysis of silver nanoparticles were evaluated.The main contents of this paper including two aspects as followed:Firstly,APTES was added into the reaction system where silver nanoparticles were fabricated by using L-ascorbic acid(AA)as reducing agent and the role of APTES was investigated in this synthesis process.The results suggested that silver nanoflowers with branch length from10 nm to 80 nm can be prepared through the control of the concentration of APTES,the mixing time of APTES and silver nitrate,the ratio of AA to silver nitrate and the reaction temperature.When the ratio of APTES to silver nitrate was less than 10:1,APTES and silver nitrate formed stable complex,that influence the anisotropic growth of silver nanoflowers.When the ratio of APTES to silver nitrate was larger than10:1,the large and spherical silver nanoparticles(approximately 250nm)were obtained.Secondly,we prepared three groups of silver nanoflowers which branch length were 80 nm,30 nm and 10 nm under the condition that the ratio of APTES and silver nitrate was 2:1,4:1 and 8:1.The silver nanoparticles exhibited good stability after 72 h of storage at room temperature.Surface-enhanced Raman scattering(SERS)performance and catalytic activity of silver nanoflowers with different branch length were evaluated.SERS results indicated the as-prepared silver nanoflowers showed good SERS activity to Rhodamine 6G and methylene blue.The silver nanoflower with 80 nm of branch length showed the best SERS activity and the enhanced factor was 10~6.Additionally,these silver nanoflowers with different branch length also can successfully catalyze the reduction of p-nitroaniline with sodium hydride in the aqueous phase.