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Study On Controllable Synthesis Of Silver - Based Nanomaterials And Application Of Surface - Enhanced Raman Spectroscopy

Posted on:2015-03-24Degree:DoctorType:Dissertation
Country:ChinaCandidate:Q L HuangFull Text:PDF
GTID:1101330470982338Subject:Analytical Chemistry
Abstract/Summary:PDF Full Text Request
Noble metal nanoparticles especially silver nanoparticles has been an important research direction spectrum due to its adjustable plasmon preperties. There are many reports on the morphology control of silver nanosturctures. Since its discovery, surface enhanced Raman scattering (SERS) phenomenon has attracted strong interest from many spectral analysts. Many Ag nanostructures with various morphologies were developed due to its high performance of surface enhanced Raman scattering. Three dimensional complex silver nanostructure has more "hot" spots because of its rough surface structure and large specific surface area. Theory and experiment show that these "hot spots" structures have better enhanced scattering effect. Based on these advantages, this paper studied the synthesis and surface enhanced Raman scattering (SERS) application of complex 3D Ag nanostructures. The main contents are as follows:1.3D Ag nanostructures with different surface chemical properties, morphology and size were prepared by a simple chemical reduction method with ascorbic acid and hydrazine hydrate as reducing agent in prensence of potassium hydrogen phthalate as the inorganic additives. The samples were characterized by ultraviolet visible light absorption spectrum, transmission electron microscope and scanning electron microscopy. The mechanism of morphology control was also discussed. The SERS performance was investigated with rhodamine 6G as a probe molecule.2. A series of silver nanostructures were prepared using green chemistry method with hydrazine hydrate as reductant and H2O2 as inorganic additives. The morphology, size and the growth mechanism of as-prepared samples were systematic studied. The synthesis condition of SERS subtrates were optimized with rhodamine 6G as the target molecules. Trace of R6G content in chili powder was tested using the optimal SERS substrate and good results were achieved.3. Silver spheres assembled with nanoplates were synthesized by a simple chemical reduction method with ascorbic acid as reducing agent in prensence of ammonium citrate as the inorganic additives. Its formation mechanism and the SERS performance were studied in detail. In order to improve SERS repeatability, AgI nanoparticles were grown on the surface of silver microspheres. After modification, the repeatability of SERS has greatly improved and the nano-composite material can also be used as photocatalyst in degradation of organic matter. 4. Silver nanoparticles on commercially available filter paper as SERS substrates were obtained by a simple, cheap and green method and its relevant parameters was optimized. Different concentrations of thiophenol, p-thiocresol and amino thiophenol as a probe molecule were used to detect the SERS activity. Experiments show that used filter paper SERS substrates have good SERS enhancement performance for several kinds of organic matter.
Keywords/Search Tags:Ag nanostuctures, controllable synthesis, spectral analysis, SERS, R6G
PDF Full Text Request
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