Investigation of Photodeposition of Gold on Titanium Dioxide Nanoparticles

Author: Abdulrahman Alotabi

Alotabi, Abdulrahman, 2017 Investigation of Photodeposition of Gold on Titanium Dioxide Nanoparticles, Flinders University, School of Chemical and Physical Sciences

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Abstract

In this work, we have investigated the photodeposition of gold (Au) on titanium dioxide (TiO2) under different conditions. Nanoparticles of gold were prepared and loaded on titanium dioxide (TiO2) using a method of photodeposition, and employed complementary techniques for example as X-ray Photoelectron Spectroscopy (XPS), Neutral Impact Collision Ion Scattering Spectroscopy (NICISS), UV photoelectron spectroscopy (UPS), and Scanning Electron Microscopy (SEM) to obtain information about the photodeposition properties of gold under a range of deposition conditions. Two types of gold were used in the study; (i) Chloroauric acid [HAuCl4], and (ii) Au clusters [Au9 (PPh3)8)] (NO3)3. The samples prepared were illuminated using UV light and radiation generated by a solar simulator to study the effect of spectral range of illumination sources. The HAuCl4 had been pre-irradiated to study the effect of photo-reduction of HAuCl4; employed pulsed and continuous irradiation techniques to study the effect of irradiation technique; varied the exposure time to study its effect; the effect of removing the phosphorus ligands from Au9 by annealing, and lastly, varied the concentration of the samples to study the effect on the Au NPs and Au9 clusters. It was found that it may the UV light activates both the Au compound and the TiO2 faster than solar simulator to form Au NPs on the surface. Pre-irradiation and longer exposure times to UV light increases the amount of Au NPs deposited on the surface of TiO2. At higher concentrations of chloroauric acid and Au clusters, more Au NPs are photodeposited on TiO2. Under the effect of irradiation technique, it was found that more Au NPs are deposited on the surface of TiO2 using pulsed technique than using continuous technique. It was also observed that heat treatment of Au9 samples resulted to partial agglomeration leading to formation of larger Au particles except the lower concentration (0.001mM). They formed clusters on the surface.

Keywords: photodeposition gold titanium dioxide NICISS SEM XPS UPS
Subject: Chemistry thesis

Thesis type: Masters
Completed: 2017
School: School of Chemical and Physical Sciences
Supervisor: Professor Gunther Andersson