Title: Photocatalytic degradation of reactive orange 16 dye over Au-doped TiO2 in aqueous suspension

Authors: Ruey Chang Hsiao, L. Selva Roselin, Hsiu-Ling Hsu, Rosilda Selvin, Ruey Shin Juang

Addresses: Department of Chemical and Materials Engineering, Lunghwa University of Science and Technology, 300, Wan-shou Rd., Sec. 1, Kueishan, Taoyuan, Taiwan; Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li, 320, Taiwan. ' Innovation Centre, Don Bosco Institute of Technology, Kurla (W), Mumbai 400 070, India. ' Department of Chemical and Materials Engineering, Lunghwa University of Science and Technology, 300, Wan-shou Rd., Sec. 1, Kueishan, Taoyuan, Taiwan. ' Department of Chemical and Materials Engineering, Lunghwa University of Science and Technology, 300, Wan-shou Rd., Sec. 1, Kueishan, Taoyuan, Taiwan. ' Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li, 320, Taiwan

Abstract: The effect of nanosized Au deposits on TiO2 particles for the photocatalytic degradation of reactive orange 16 dye (RO 16) as model compound was investigated. The deposition of Au on TiO2 was carried out by deposition-precipitation (DP). The catalysts were characterised by XRD, TEM, and XPS analyses. The photocatalytic experiments were carried out under a radiation source of low-pressure mercury vapour lamp (6 W) emitting ultraviolet light with maximum intensity at 253.7 nm. The Au deposits significantly enhanced the degradation rate of the dye. The significant enhancement of the Au/TiO2 photocatalyst can be ascribed to the trapping of photogenerated electrons by nano-sized gold particles, which subsequently increase the lifetime of the photogenerated hole for oxidation process and also increased light absorption by crystalline defects. The catalytic activity was found to be dependent on the metal content on TiO2 and showed a maximum at 2 wt% Au. The amount of catalyst was optimised as 2.5 g/L. The photocatalytic activity was strongly dependent on the initial pH of the suspension; pH values in the range 5-10 showed better activity, whereas highly acidic and basic suspensions resulted in a considerable decrease in the activity.

Keywords: photooxidation; Au/TiO2 catalyst; deposition precipitation; dye degradation; gold nanoparticles; titanium dioxide; nanotechnology; reactive orange 16 dye.

DOI: 10.1504/IJMATEI.2011.037882

International Journal of Materials Engineering Innovation, 2011 Vol.2 No.1, pp.96 - 108

Published online: 01 Jan 2011 *

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