Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.552337
Title: Structural and catalytic studies of novel Au/Ni enantioselective catalysts
Author: Trant, Aoife Geraldine
Awarding Body: University of St Andrews
Current Institution: University of St Andrews
Date of Award: 2008
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Abstract:
Heterogeneous enantioselective catalysis strives to create new successful catalysts. One of the most researched examples is the hydrogenation β-ketoesters using nickel-based catalysts. A hindrance in the industrial scale-up of this enantioselective hydrogenation reaction is the lack of exact details of how chirality is bestowed onto this achiral metal surface. While a number of mechanisms have been proposed to explain the enantioselective behaviour of this system, these are predominantly based on catalytic studies. An alternative approach is through surface science studies examining the morphology, structure and composition of this catalytic system. A range of ultrahigh vacuum based model studies investigating the structure and composition of ultrathin Ni films and Ni/Au surface alloys on Au{111} using the techniques of Scanning Tunnelling Microscopy (STM) and Medium Energy Ion Scattering (MEIS) are presented in this thesis. In addition, the adsorption of the chiral modifier (S)-glutamic acid has been studied on these surfaces using vibrational spectroscopy (Reflection Absorption Infrared Spectroscopy (RAIRS)) and Temperature Programmed Desorption (TPD). Furthermore, MEIS has been used to investigate the influence of (S)-glutamic acid on the surface composition of Au/Ni model catalysts detecting effects such as adsorbate induced segregation and de-alloying behaviour. In addition, colloidal preparative routes have been used to synthesise bimetallic Au/Ni nanoparticles supported on mesoporous silica. The catalysts are then modified by the adsorption of the chiral ligand, (R,R)-tartaric acid. Finally, the catalysts are tested for their activity and enantioselectivity with respect to methylacetoacetate hydrogenation. At each stage the catalysts are characterised by a combination of Extended X-ray Absorption Fine Structure (EXAFS); Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectrometry (EDS) and Atomic Absorption Spectroscopy (AAS).
Supervisor: Baddeley, C. J. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.552337  DOI: Not available
Keywords: QD505.T8 ; Enantioselective catalysis ; Gold alloys ; Nickel catalysts ; Catalysts
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