Selective Oxidations Using Colloidal Metal Particles with Non-Innocent Ligands

The project will fall at the boundary of heterogeneous catalysis, materials synthesis and colloidal science. Traditionally heterogeneous catalysis has been based on supporting precious metal nanoparticles on high surface area oxides or carbons to improve stability. However; supporting these particles forces them from there solution phase equilibrium structure. The particles become faceted in order to increase their interaction with the support material and in some cases this is detrimental to catalytic activity. Recently we have shown that by forming bimetallic nanoparticles which are stabilised with polymers in the liquid phase, rather than solid oxide materials certain challenging reactions can be carried out with high rates that are supressed with the faceted particles.

One such challenging reaction is the selective oxidation of terminal hydrocarbon C-H such as methane, ethane, propane and liquid phase substrates such as cyclohexane. The project will investigate the effect of using colloidal particles rather than solid catalysts for the selective oxidation of these molecules to primary alcohols, which are important industrially. Understanding of the material synthesis is crucial in order to control particle size and composition and is not trivial at the nanoscale. One area of the colloidal synthesis that is not commonly investigated it the effect of the ligand used to stabilise the particles. Recent results have suggested that the polymer can affect the composition of the metal particles, the nature of the surface and the structure of the particle. By carful control of the ligand design, through the use of systematic molecule (N-heterocyclic carbenes) or polymer libraries, the effect of the electron donation or withdrawal from the metal particles on reactivity can be studied. Hence the aim of this PhD project will be to study the effect of decorating colloidal nanoparticles with these ligands and studying the effect on catalysed reactions involved in alkane activation.