Part I: In situ pulse electrochemical deposition of platinum nanoparticles for efficient catalyst utilization in fuel cells. Part II: Fabrication and characterization of polyelectrolyte-quantum dot hybrid structures using layer-by-layer self assembly

This thesis work is entirely committed towards extensive research on application of polyelectrolytes/polyelectrolyte membranes on the fields of materials science and electroanalytical chemistry.Part I highlights development of new electroanalytical techniques to deposit the electrocatalyst in proton exchange membrane (PEM) fuel cells. In this section of thesis work the major directions are to improve our basic knowledge and understanding factors limiting the efficient use of the electrocatalyst in fuel cells and develop and optimize a means for overcoming these limitations. Initially systematic studies will be performed to identify the limitations associated with the commercially available fuel cells followed by optimizing and utilizing the methods developed in this thesis work to manufacture functioning hydrogen PEM fuel cells using NafionRTM membrane via in situ electrodeposition of Pt. This research involves a detailed optimization of the pulse electrodeposition technique to deposit Pt using NafionRTM membrane as a template. Characterization of these experiments were done using techniques such as Cyclic Voltammetry (CV), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Secondary Ion Mass Spectrometry (SIMS), Energy Dispersion X-ray Spectrometry (EDX) and Inductively Couple Plasma (ICP). Finally construction of hydrogen fuel cells was done by in situ pulse electrochemical deposition through complete membrane electrode assemblies.Much of the attention of Part II is dedicated to construct and characterize polyelectrolyte and quantum dot hybrid multilayer structures. Much of the attention is focused towards investigation of the Forster energy transfer processes between the donor polyelectrolytes (poly-p-phenylelvinylene, PPV) and the acceptor ZnS/CdSe core/shell quantum dots with respect to its separation. The work shown in Chapter 7 explains the process of introduction of quantum dots to these multilayer thin films and analysis of these hybrid structures using Laser Scanning Confocal Microscopy (LSCM), excited state life time decay studies and UV-Vis absorption studies.