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Title: Platinum intermetallic compounds as heterogeneous catalysts for the hydrogenation of unsaturated aldehydes
Author: Galloway, E.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2009
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The research presented in this thesis is focussed on the catalytic behaviour of platinum intermetallic compounds. The catalytic reaction studied is the hydrogenation of the α,β-unsaturated aldehyde, crotonaldehyde, to produce the corresponding unsaturated alcohol, crotyl alcohol. Amongst the large variety of catalysts tested to date that possess high selectivity to crotyl alcohol have been supported Pt/M alloyed particles, with and without a catalyst promoter. The work presented in this thesis uses phase-pure unsupported PtM intermetallic compounds as catalysts for the heterogeneous chemoselective hydrogenation of crotonaldehyde in micro-reactor experiments. The systematic catalyst synthesis method of each intermetallic compound catalyst allows for accurate characterisation and assignment of the active catalytic phases. The characterisation of the binary intermetallic Pt compounds was carried out using X-Ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Temperature Programmed Desorption/Reactions (TPD/R) and Transmission Electron Microscopy (TEM). The intermetallic compounds studied were: PtCd, PtFe, PtZn and Pt2Zn11. This resulted in the first observations of Pt2Zn11 and PtCd as catalysts in the hydrogenation of crotonaldehyde. Using XPS, this thesis addresses two current gaps in current understanding of heterogeneous catalysis with respect to these systems: (i) the electronic modification of Pt-Zn catalysts by halogens and the resulting effects on the chemoselectivity of crotonaldehyde hydrogenation; (ii) the intrinsic selectivity of the phase-pure intermetallic compounds PtZn Pt2Zn11, PtFe and PtCd, with known surface compositions; and (iii) the effect of changing the surface composition of the intermetallic compounds on their heterogeneous catalytic activity. An ultra-high vacuum (UHV) study, utilising TPD/R was also employed to increase understanding of the adsorption and reaction properties of crotonaldehyde and its hydrogenation products on the highly selective PtZn catalyst surface.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available