Synthesis of Au Ag CdS Nanostructures Effect of Size and Shape on Photocatalytic Activity

Abstract

This thesis presents a fine insight into many aspects of nanostructures and their applications in photocatalysis. Au/Ag and#8722; Cadmium sulfide (CdS) nanostructures viz., nanospheres, nanorods and nanowires of different dimensions have been synthesized to investigate the effect of size, shape, nature and spatial orientations of co-catalyst onto the change in photophysical, (absorbance, photoluminescence, relaxation lifetimes) and photocatalytic properties to achieve the best information in CdS nanostructures. The present thesis is divided into eight chapters: Chapter 1: Introduction The first chapter introduces the brief aspects and literature survey on semiconductor nanostructures with photocatalysis as an application point of view. Specific attention has been paid on cadmium sulfide (CdS) vis-à-vis their structure, morphology, their heterocomposites with coinage metals. Chapter 2: Synthesis and Experimental Techniques The second chapter gives a brief description of various techniques used for synthesis and characterize pure and Au/Ag-CdS nanocomposites. CdS nanostructures of different morphologies viz.; nanospheres, nanorods and nanowires have been synthesized by reverse micelles method, solvothermal and anodic alumina membrane (AAM) template techniques. Coinage metals were introduced onto CdS surface by means of in-situ deposition, photodeposition, impregnation and doping techniques. To understand the potential of CdS nanostructures, a deeper knowledge of their overall properties is required. Therefore, the synthesized materials have been characterized by UV-vis, Diffused absorbance, Photoluminescence and Time resolved spectroscopy, Scanning electron microscope (SEM), Field emission-electron microscope (FE-SEM), Low resolution (TEM) and High resolution (HRTEM) Transmission microscope, BET surface analyzer, X-ray diffraction study. Electrical properties (resistance, current, voltage and conductance) were studied by current-voltage (IV) characteristics curves.