Glover, EN;
(2017)
Design, synthesis and characterisation of novel materials for photocatalytic water splitting.
Doctoral thesis , UCL (University College London).
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Abstract
Rh-doped and Rh/Sb codoped TiO2 and SrTiO3 powders have been synthesised by solid state reaction of the titanate with the appropriate dopant oxides. The resultant materials have been extensively analysed in order to elucidate their physical, electrical and optical properties in order to determine their characteristics as photocatalyst materials. Powder X-ray diffraction provided information regard phase purity of the samples and indicated that for SrTiO3, direct synthesis of doped materials from the titanate is not possible for total dopant concentration > 1.5 mol. %. A preliminary study indicated that the Sb dopant oxidation state cannot be inferred from photoelectron core line position measured by X-ray photoelectron spectroscopy (XPS) and so X-ray absorption measurements were recorded in both cases. For TiO2 the presence of Sb (V) was strongly indicated both by the Sb K-edge energy and the EXAFS derived Sb-O bond lengths. In SrTiO3, due to the low concentrations of dopant ion, results were inconclusive. Since the existence of Rh4+/Rh3+ in these materials affects the Fermi level position, which is calibrated as 0 eV in XPS, careful handling of XPS data was required. The valence band and O 1s core line spectra were utilised to indicate the position of Fermi level in these materials. Transient absorption spectroscopy was used to probe the charge carrier dynamics of some selected materials and indicated that while the high dopant concentrations in TiO2 appeared to supress charge carrier formation and increase recombination, low concentrations of dopants in SrTiO3 show no negative effects with respect to pristine SrTiO3 powder.
| Type: | Thesis (Doctoral) |
|---|---|
| Title: | Design, synthesis and characterisation of novel materials for photocatalytic water splitting |
| Event: | University College London |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1574549 |
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