Acta Phys. -Chim. Sin. ›› 2010, Vol. 26 ›› Issue (10): 2733-2738.doi: 10.3866/PKU.WHXB20101007

• CATALYSIS AND SURFACE STRUCTURE • Previous Articles     Next Articles

Photoinduced Charge Carrier Properties and Photocatalytic Activity of N-Doped TiO2 Nanocatalysts

ZHANG Xiao-Ru, LIN Yan-Hong, ZHANG Jian-Fu, HE Dong-Qing, WANG De-Jun   

  1. College of Chemistry, Jilin University, Changchun 130012, P. R. China
  • Received:2010-05-21 Revised:2010-07-16 Published:2010-09-27
  • Contact: LIN Yan-Hong E-mail:linyh@jlu.edu.cn
  • Supported by:

    The project was supported by the National Key Basic Research Programof China (973) (2007CB613303), National Natural Science Foundation of China (20703020, 20873053), and Scientific Forefront and Interdisciplinary Innovation Project, Jilin University, China (421031401412).

Abstract:

Nitrogen-doped TiO2 (N-TiO2) photocatalysts with different amounts of N doping were successfully synthesized by the hydrothermal method using urea as the nitrogen source. The samples were characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (UV -Vis DRS),X -ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The photodegradation of rhodamineB (RhB) and methyl orange (MO) solutions was used to evaluate the photocatalytic activity of the catalysts under UV and visible light irradiation. Surface photovoltage (SPV) and transient photovoltage (TPV) techniques were used to investigate the separation and transport mechanism of the photogenerated charge carriers of the N-doped TiO2 nanoparticles. The relationship between the photogenerated charge carriers and photocatalytic activity was also discussed. The results showed that the SPV threshold values shifted to the visible region and a stronger photovoltaic response in the visible region was observed with an increase in N doping. We also found that the maximum TPV response time was different for N-TiO2. These results indicate that with an appropriate amount of N doping, the photoinduced charge carriers separate efficiently, the transmission time increases, and the lifetime of the photoinduced charge carriers increases. Therefore, the photocatalytic activity is enhanced. However, excessive N acts as recombination centers for photoinduced electrons and holes, which reduces their photocatalytic activity.

 

Key words: N-doped TiO2, Surface photovoltage, Transient photovoltage, Photo-induced charge carrier, Photocatalytic activity

MSC2000: 

  • O643