Novel routes to metal nanoparticles: Electrodeposition and reactions at liquid|liquid interfaces

This thesis considers the nucleation and growth, synthesis, and catalytic application of metallic nanoparticles at liquid|liquid interfaces. It comprises five publications, a previously unpublished synthesis of polymer coated palladium nanoparticles, and an introduction to the relevant literature. Three publications are concerned with electrodeposition of metal nanoparticles at liquid|liquid interfaces. One publication and the results presented here consider the synthesis of silver and palladium colloids by reduction with pyrrole and thiophene monomers. The fifth publication demonstrates the use of gold and palladium colloids as electrocatalysts in two-phase dehalogenation reactions. The literature reviewed serves as an introduction to nanoparticles, liquid|liquid interfaces and electrodeposition studies relevant to the publications and experimental studies presented herein. Nucleation models used are evaluated by numerical means. In the electrodeposition studies, the fundamentals of deposition reactions at liquid|liquid interfaces, involving irreversible Butler-Volmer type growth kinetics and overlap of diffusion fields are developed. The importance of applied potential, particle agglomeration and surface activity on the nucleation process is shown. Small metallic nanoparticles were synthesized in homogeneous media, using novel syntheses involving pyrrole and thiophene derivatives as both reductants and stabilizators. The use of aqueous metal colloids as catalysts for dehalogenation reactions in a two-phase immiscible electrolyte system is demonstrated. Specifically palladium or gold colloids prepared by the citrate reduction method can be negatively charged in a heterogenous two-phase reaction with decamethylferrocene, and subsequently used as an aqueous catalyst for dehalogenation of 2-bromoacetophenone.