物理化学学报 >> 2010, Vol. 26 >> Issue (10): 2733-2738.doi: 10.3866/PKU.WHXB20101007

催化和表面结构 上一篇    下一篇

N 掺杂TiO2 纳米粒子表面光生电荷特性与光催化活性

张晓茹, 林艳红, 张健夫, 何冬青, 王德军   

  1. 吉林大学化学学院, 长春130012
  • 收稿日期:2010-05-21 修回日期:2010-07-16 发布日期:2010-09-27
  • 通讯作者: 林艳红 E-mail:linyh@jlu.edu.cn
  • 基金资助:

    国家重点基础研究发展规划项目(973) (2007CB613303),国家自然科学基金(20703020, 20873053)和吉林大学科学前沿与交叉学科创新项目(421031401412)资助

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).

摘要:

以尿素为氮源, 采用水热法制备了不同N 掺杂量的TiO2 (N-TiO2)光催化剂. 利用X 射线衍射(XRD), 紫外-可见漫反射光谱(UV-Vis DRS),X 射线光电子能谱(XPS) 及荧光(PL) 光谱等技术对其进行了系统的表征. 以罗丹明B (RhB) 和甲基橙(MO) 溶液的脱色降解为模型反应, 分别考察了N-TiO2 光催化剂在紫外和可见光区的光催化活性. 利用表面光伏(SPV) 和瞬态光伏(TPV) 技术研究了N-TiO2 纳米粒子表面光生电荷的产生和传输机制, 并探讨了光生电荷与光催化活性之间的关系. 结果显示, 随着N 含量的增大, TiO2 表面光伏响应阈值红移, 可见光部分光电压响应强度逐渐增强, 瞬态光伏响应达到最大值的时间亦有着不同程度的延迟. 这表明适量的N 掺杂能够提高TiO2 纳米粒子中光生载流子的分离效率, 相应地延长载流子的传输时间, 增加光生电荷的寿命, 从而促进其光催化活性; 而过量的N 掺杂则增加了TiO2 纳米粒子中光生载流子的复合中心, 抑制其光催化活性.

 

关键词: N 掺杂TiO2, 表面光伏, 瞬态光伏, 光生电荷, 光催化活性

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