DSpace JSPUI

In the present thesis, different aspects of nanoscience and nanotechnology and the characteristic properties of nanoparticles have been discussed. Leaving aside the synthetic strategy and mode of stabilization of metal and metal oxide nanoparticles, their potential applications in catalysis and surface enhanced Raman scattering studies have been presented in detail. In a step-wise fashion, a series of nanostructured materials have been fabricated and characterized by different physical techniques to elucidate the structural aspects. In the 2nd part of the thesis, shape-selective synthesis of exclusively single crystalline β-MnO2 nanoparticles in variable micellar templates under alkaline condition at room temperature and their catalytic activity have been depicted. Raman measurement, cyclic voltammetry and transmission electron microscopy have been exploited to confirm the changes in the structural aspects of the nanoparticles. Afterwards, the synthesis of β-MnO2 nanoparticles has also been carried out in non polar organic solvents and used as a photo-catalyst for oxidative phenol coupling reaction. In addition to the β-phase of MnO2, a green chemistry approach has been developed to obtain α- MnO2 nanocomposite which acts a solid phase catalyst for hydrolysis of a series of nitriles. After that, a facile synthetic protocol has been furnished to obtain normal as well as inverted core-shell structures of silver/gold through layer-by-layer deposition of specific metal precursor exploiting electrostatic field force out of the charged resin matrix. Novelty of this work has been elaborated considering the catalytic efficiency of these composite materials for the synthesis of important amino compounds. The protocol eliminates the inherent difficulty of product separation. Finally, Ag nanoparticle prompted formation of novel hierarchical flower-like nanostructures of MnO2 has been achieved by facile wet chemical and photochemical routes. Thus, inactive MnO2 substrates become SERS active. This study opens a new avenue to study surface enhanced Raman scattering with rhodamine 6G and 2-aminothiophenol as probe molecules. Keywords: Manganese Dioxide, Shape-Controlled Synthesis, Organosol, Nanocomposites, Layer-by-Layer, Doping, Nanoflower. vii