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International Journal of Photoenergy
Volume 2013, Article ID 439079, 9 pages
Research Article

Preparation of N- Using a Microwave/Sol-Gel Method and Its Photocatalytic Activity for Bisphenol A under Visible-Light and Sunlight Irradiation

1Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80778, Taiwan
2Department of Safety Health and Environmental Engineering, National Yunlin University of Science and Technology, Yunlin 64002, Taiwan
3Department of Environmental Engineering, National Ilan University, Ilan 26041, Taiwan

Received 20 November 2012; Revised 4 January 2013; Accepted 13 January 2013

Academic Editor: Mahmoud M. El-Nahass

Copyright © 2013 Chung-Hsin Wu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This study applied the microwave/sol-gel method to prepare nitrogen-doped TiO2 (N-TiO2). The N-TiO2 was immobilized in glass balls to form N-TiO2/glass beads and applied to degrade Bisphenol A (BPA) under visible-light and sunlight irradiation. The characteristics of the prepared photocatalysts were analyzed by X-ray diffraction (XRD), UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Experimental results demonstrate that the percentage of anatase increased as the amount of N in N-TiO2 increased. Compared with the undoped TiO2 (420 nm), spectra show that the absorption edge shifted to a longer wavelength (445 nm) after N doping. The XPS characterization confirms the substitution of crystal lattice O to N species in N-TiO2, forming Ti–O–N and N–Ti–O. With an increased N/Ti ratio, photodegradation efficiency increased and then decreased; moreover, the optimal amount for N doping was determined as an N/Ti mole ratio of 0.08 (0.1 NT). The efficiency of 0.1 NT in doing BPA photodegradation was greater than that of Degussa P25. After reaction for 61 min, the mineralization percentage of 0.1 NT under visible-light irradiation reached 41%. Photocatalyst efficiency decreased as the number of repeats increased in the visible-light/N-TiO2 system; however, these systems were stable during reaction.