UCL Discovery

Abstract

This work of this thesis covers a number of different aspects of chemistry. Initially, the relationship between the number of atoms at the core of molecular clusters of gold and the steric bulk of the stabilising phosphine ligands is explored. A range of gold clusters was prepared through the use of increasingly bulky phosphine ligands. Theses clusters were characterised using a number of techniques to gain an insight into their structures. Catalysis chemistry was investigated by using the clusters to synthesise heterogeneous catalysts. The effect of varying the loading and calcination temperature of the catalysts on their catalytic activity for the oxidation of benzyl alcohol was researched. A number of standard (XRD, TEM) and advanced characterisation (in situ XAS) methods were utilised to determine the effect on the catalyst structure by calcination temperature and gold loading. The relationship between the catalytic activity and the size of the cluster used to prepare the catalyst, as well as the type of catalyst support used, was also examined. Synchrotron radiation allowed for in situ experiments to be designed and utilized in order to learn about a new low temperature peroxide assisted ligand removal process as an alternative to calcination. This method proved to enable more control over the rate of phosphine loss and could possible be used to activate other ligand-stabilised clusters for catalysis.

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