Photocatalytic application of porous Au/TiO2 nano-hybrids prepared by a templating technique
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Date
2008-07-30
Authors
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Journal ISSN
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Publisher
International Conference on the Photochemical Conversion and Storage of Solar Energy
Abstract
Gold doping or deposition in TiO2 can effectively improve the photocatalytic performance of the titania by either modifying the bandgap and thereby inducing photoactivity under visible light or decreasing the recombination of excited electron and hole. Templating techniques can produce materials with designed morphology and porosity. The objective of this project was to couple controlled porosity allowing faster molecule diffusion through the porous channels with gold deposition to further increase the photocatalytic activity of TiO2.
Templating and sol-gel techniques were combined to synthesise Au/TiO2 nano-hybrids with improved photocatalytic activity. The porous structures directed by the agarose gel template were examined by SEM. X-ray diffraction analysis ascertained the materials to be anatase phase, and the gold peaks were observed when the gold content was over 0.25 wt%. TEM further confirmed the highly porous structure of the composites (Figure 1). The gold particle sizes, influenced by both the synthesis methods and initial gold content, ranged from ~ 2 to 40 nm. The gold distribution and content were identified by means of secondary ion mass spectrometer and inductively coupled plasma mass spectrometry, respectively. Finally, the catalytic performance of the Au/TiO2 was assessed by photodecomposition of methylene blue under UV light. The influence of parameters such as synthesis methods, material properties and photocatalytic test conditions (e.g., pH, catalyst and dye concentration) on the photocatalytic efficiency was also investigated. The photocatalytic efficiency improved by a maximum 40% for the Au/TiO2 sample with a gold particle size of 2 nm and 2 wt % gold content.
Description
Hardcopy held by ANSTO Library at DDC 621.48/7
Keywords
Gold, Titanium, Photocatalysis, Excited states, Materials, Morphology, Porosity, Deposition, X-ray diffraction, Scanning electron microscopy
Citation
Wang, X., Mitchell, D. R. G., Prince, K., & Caruso, R. A. (2008). Photocatalytic application of porous Au/TiO2 nano-hybrids prepared by a templating technique. Paper presented to the 17th International Conference on Photochemical Conversion and Storage of Solar Energy 2008, Sunday 27 July - Friday 1 August 2008, Sydney Convention and Exhibition Centre, Australia. (pp.116)