Chinese Journal of Catalysis ›› 2018, Vol. 39 ›› Issue (4): 867-875.DOI: 10.1016/S1872-2067(17)62999-1

• Articles • Previous Articles    

Photocatalytic performance of TiO2 nanocrystals with/without oxygen defects

Kezhen Qia, Shu-yuan Liub,c, Meng Qiud   

  1. a Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang 110034, Liaoning, China;
    b Department of Pharmacology, Shenyang Medical College, Shenyang 110034, Liaoning, China;
    c Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education), College of Chemistry, Nankai University, Tianjin 300071, China;
    d College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, Guangdong, China
  • Received:2017-11-20 Revised:2017-12-30 Online:2018-04-18 Published:2018-04-08
  • Contact: 10.1016/S1872-2067(17)62999-1
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (51602207), the Doctoral Scientific Research Foundation of Shenyang Medical College (20174043), the Scientific Research Project for University Students of Shenyang Medical College (20160809), and the Doctoral Scientific Research Foundation of Liaoning Province (201601149, 20170520011).

Abstract:

To investigate the role of oxygen defects on the photocatalytic activity of TiO2, the TiO2 nanocrystals with/without oxygen defects are successfully synthesized by the hydrothermal and sol-gel methods, respectively. The as-prepared TiO2 nanocrystals with defects are light blue and the absorption edge of light is towards the visible light region (~420 nm). Raman and X-ray photoelectron spectroscopy (XPS) measurements all confirm that the concentration of oxygen vacancies in the TiO2 synthesized by the sol-gel method is less than that synthesized through the hydrothermal route. The introduction of oxygen defects contributes to a new state in the band gap that narrows the band gap, which is the reason for the extension of light absorption into the visible light region. The photocurrent results confirm that this band-gap narrowing enhances the photocurrent response under simulated solar light irradiation. The TiO2 with oxygen defects shows a higher photocatalytic activity for decomposition of a methylene blue solution compared with that of the perfect TiO2 sample. The photocatalytic mechanism is discussed based on the density functional theory calculations and photoluminescence spectroscopy measurements.

Key words: TiO2, Defect, Optical property, Photocatalytic activity, Density functional theory calculation