Preparation Of Silver Nanoparticles By Photoreduction Of Cyclic Acetal

Nowadays, nanotechnology is one of the most interesting areas, which studied atomic scale materials and devices. Silver nanoparticles, have a long history in terms of preparation, characterization, and application. Silver nanoparticles processes different physical chemical properties, including high electrical conductivity, thermal conductivity, catalytic activity, etc. Silver nanoparticles has been widely applied to medicine, cosmetic, renewable energy sources, etc. The photochemical synthesis method has been applied in synthesizing single metal, bimetal nanoparticles and composites for its very versatile and convenient process. In this thesis, silver nanoparticles were prepared by 1,3-Benzodioxole (BDO) which was a kind of plant extracts and environmental friendly reducing agent. The reaction mechanism and equation had also been proved. The main research work are shown below:1. The photochemical reduction route has been designed to prepare silver nanoparticles with cyclic acetal compounds. Through the exploration of reaction conditions, the silver nitrate was chosen as the precursor, ethanol as the solvent, and mercury lamp as light source. Results of XRD and TEM showed that the product was silver particles at nanoscale.2. The influence factors of reaction system have been studied: different types of cyclic acetal compounds, solution concentration and reaction temperature of the system. The size of the nanoparticles was highly affected by solution concentration. The size of nanoparticles rose with the increase of concentration. Though, the particle size distribution became broader than before. When solution concentration was 10-4 mol/L, the surface plasma absorption band of the silver nanoparticles synthesized and particle size distribution was relatively narrow. When the concentration increased to 0.01 mol/L, the silver nanoparticles became unstable. Meanwhile, some part of the nanoparticles that suspended in the solution began to form precipitation. Surface plasma absorption band and particle size distribution became wider than before.3. The reaction mechanism was studied with UV-Vis spectroscopy and gas chromatography mass spectrometry instrument. BDO produced free radicals under the UV irradiation. Silver ions were reduced by free radicals to zero valent state, and hydrogen atom of ethanol solvent molecules had participated in the photoreaction. Zero valent state of silver atoms grew by nucleation and became silver nanoparticles.