Anodic Growth of Highly Ordered Titanium Oxide Nanotube Arrays: Effects of Critical Anodization Factors on their Photocatalytic Activity
Highly ordered arrays of TiO2 nanotubes (TiNTs) were grown vertically on Ti foil by electrochemical anodization. We controlled the lengths of these TiNTs from 2.4 to 26.8 ¶üÇóμm while varying the water contents (1, 3, and 6 wt%) of the electrolyte in ethylene glycol in the presence of 0.5 wt% NH4F with anodization for various applied voltages (20–80 V), periods (10–240 min) and temperatures (10–30 oC). For vertically aligned TiNT arrays, not only the increase in their tube lengths, but also their geometric (wall thickness and surface roughness) and crystalline structure lead to a significant influence on photocatalytic activity. The length optimization for methylene blue (MB) photodegradation was 18 μm. Further extending the TiNT length yielded lower photocatalytic activity presumably related to the limited MB diffusion and light-penetration depth into the TiNT arrays. The results indicated that a maximum MB photodegradation rate was obtained for the discrete anatase TiO2 nanotubes with thick and rough walls.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1059473Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2406
 Mills, A., Davies, R. H., and Worsley, D., "Water purification by semiconductor photocatalysis," Chem. Soc. Rev., vol. 22, pp. 417-425, 1993.
 Asahi, R., Morikawa, T., Ohwaki, T., Aoki, K. and Taga, Y., "Visible-light photocatalysis in nitrogen-doped titanium oxides," Science., vol. 293, pp. 269-271, 2001.
 Li, X. Z. and Li, F. B., "Study of Au/Au3+-TiO2 photocatalysts toward visible photooxidation for water and wastewater treatment," Environ. Sci. Technol., vol. 35, pp. 2381-2387, 2001.
 Lee, J. C., Kim, M. S., and Kim, B. W., "Removal of paraquat dissolved in a photoreactor with TiO2 immobilized on the glass-tubes of UV lamps," Water Res., vol. 36, pp. 1776-1782, 2002.
 Zhang, X., Pan, J. H., Du, A. J., Fu, W., Sun, D. D., Leckie, J. O., "Combination of one-dimensional TiO2 nanowire photocatalytic oxidation with microfiltration for water treatment," Water Res., vol. 43, pp. 1179-1186, 2009.
 Kar, A., Smith, Y. R., and Subramanian, V., "Improved photocatalytic degradation of textile dye using titanium dioxide nanotubes formed over titanium wires. Environ," Sci. Technol., vol. 43 (9), pp. 3260-3265, 2009.
 Kumar, P. S. S., Sivakumar, R., Anandan, S., Madhavan, J., Maruthamuthu, P., and Ashokkumar, M., "Photocatalytic degradation of Acid Red 88 using Au-TiO2 nanoparticles in aqueous solutions," Water Res., vol. 42, pp. 4878-4884, 2008.
 Wu, J. J. and Tseng, C. H., "Photocatalytic properties of nc-Au/ZnO nanorod composites," Appl. Catal. B: Environ., vol. 66, pp. 51-57, 2006.
 Gong, D., Grimes, C. A., Varghese, O. K., Hu, W., Singh, R. S., Chen, Z., and Dickey, E. C., "Titanium oxide nanotube arrays prepared by anodic oxidation," J. Mater. Res., vol. 16 (12), pp. 3331-3334, 2001.
 Tsuchiya, H., Macak, J. M., Ghicov, A., Taveira, L., Balaur, E., Ghicov, A., Sirotna, L., and Schumuki, P., "Self-organized TiO2 nanotubes prepared in ammonium floride containing acetic acid electrolytes," Electrochem. Commun., vol. 7, pp. 576-580, 2005.
 Mor, G. K., Shankar, K., Paulose, M., Varghese, O. K., and Grimes, C. A., "Enhanced photocleavage of water using titania nanotube arrays," Nano Lett., vol. 5, pp. 191-195, 2005.
 Zheng, Q., Zhou, B., Bai, J., Li, L., Jin, Z., Zhang, J., Li, J., Liu, Y., Cai, W., and Zhu, X., "Self-organized TiO2 nanotube array sensor for the determination of chemical oxygen demand," Adv. Mater., vol. 20, pp. 1044-1049, 2008.
 Zwilling, V., Aucouturier, M., and Darque-Ceretti, E., "Anodic oxidation of titanium and TA6V alloy in chromic media. An electrochemical approach," Electrochim. Acta., vol. 45, pp. 921-929, 1999.
 Shankar, K., Mor, G. K., Fitzgerald, A., and Grimes, C. A., "Cation effect on the electrochemical formation of very high aspect ratio TiO2 nanotube arrays in formamide-water mixtures," J. Phys. Chem. C., vol. 111, pp. 21-26, 2007.
 Gr├ñtzel, M., "Molecular photovoltaics that mimic photosynthesis," Pure Appl. Chem., vol. 73 (3), pp. 459-467, 2001.
 Guettai, N. and Ait Amar, H., "Photocatalytic oxidation of methyl orange in presence of titanium dioxide in aqueous suspension. Part II: kinetics study," Desalination, vol. 185, pp. 439-448, 2005.
 Chanmanee, W., Watcharenwong, A., Chenthanmarakshan, C. R., Kajitvichyanukul, P., de Tacconi, N. R., and Rajeshwar, K., "Formation and characterization of self-organized TiO2 nanotube arrays by pluse anodization," J. Am. Chem. Soc., vol. 130, pp. 965-974, 2008.
 Habazaki, H., Fushimi, K., Shimizu, K., Skeldon, P., and Thompson, G. E., "Fast migration of fluoride ions in growing anodic titanium oxide," Electrochem. Commun., vol. 9, pp. 1222-1227, 2007.
 Mor, G. K., Varghese, O. K., Paulose, M., Shankar, K., and Grimes, C. A., "A review on highly ordered, vertically oriented TiO2 nanotube arrays: Fabrication, material properties, and solar energy applications," Solar Energy Materials and Solar Cells, vol. 90, pp. 2011-2075, 2006.
 Christophersen, M., Carstensen, J., Voigt, K., and F¶ÇçÀll, H., "Organic and aqueous electrolytes used for etching macro- and mesoporous silicon," Phys. Stat. sol. (a), vol. 197 (1), pp. 34-38, 2003.