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Title: Nanostructured materials as potential photocatalysts for water treatment
Author: Alghamdi, Eman
ISNI:       0000 0004 7962 1706
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2018
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This thesis discusses the latest developments in the use of nanostructured materials in water treatment. The method discussed is heterogeneous photocatalysis which uses titanium dioxide to photo-decompose organic compounds. The thesis seeks to determine the effects of the heterogeneous photocatalysis by experimental means. Methylene blue is used as the organic compound, which should be neutralised, and also acts as an indicator due to its blue colour. The objective of the experiment is to determine the optimum conditions which lead to the release of electron-hole pair. The parameters monitored are the temperature of the solution and the wavelength of the UV light. The optimum thickness of the coating of by spin coating and the modifications of titanium oxide that could increase the efficiency of the process are also determined. Group (VI) or metal transition elements-doped TiO2 nanoparticles (Cr, Mo, W) were synthesised and utilised as catalyst for the decolorisation of aqueous solution contain-ing methylene blue. FT-IR and UV-vis spectroscopy techniques, X ray diffraction (XRD), scanning electron microscopy (SEM) were used to characterise the samples. The results indicated that the doped TiO2 nanoparticles showed higher photocatalytic activity than the pure one. All doped materials display reduced activity compared to their undoped counterparts this suggests the dopant either hinders the electron transfer due to recombination or charge trapping resulting the removal of the active species away from the active sites. P25 is usually considered to be the most active catalyst due to the hetro-junction enabling efficient charge separation. The pure anatase phase is better than pure rutile, due to the relativity surface activity and stability of the respective materials. Modification of the chemical structure of TiO2 by Cr, Mo, W doping allows moving the photocatalytic activity of TiO2 towards visible light. The results indicates that films doped with 0.1% exhibit the highest UV and visible light photocatalytic activity.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QC Physics