Journal of Inorganic Materials ›› 2020, Vol. 35 ›› Issue (12): 1340-1348.DOI: 10.15541/jim20200133

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Photocatalytic Reduction of Re (VII) on Amorphous TiO2/g-C3N4 Derived from Different N Sources

WANG Xucong1,2,3(),DENG Hao3,JIANG Zhongyi1,2(),YUAN Liyong3()   

  1. 1. Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
    2. Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
    3. Laboratory of Nuclear Energy Chemistry, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-03-16 Revised:2020-04-20 Online:2020-12-20 Published:2020-06-09
  • Contact: JIANG Zhongyi, professor. E-mail: zhyjiang@tju.edu.cn; YUAN Liyong, professor. E-mail: yuanly@ihep.ac.cn
  • About author:WANG Xucong(1994–), male, Master candidate. E-mail: wangxc@ihep.ac.cn
  • Supported by:
    National Natural Science Foundation of China(21925603);National Natural Science Foundation of China(21836001);National Natural Science Foundation of China(21621004);Natural Science Foundation of Tianjin City(18JCYBJC21000)

Abstract:

To clarify the effect of N sources on the photocatalytic reduction of Re (VII) in amorphous TiO2/g-C3N4 (TCN) composites, g-C3N4 were prepared via a thermal decomposition of three precursors (Urea, Thiourea and Melamine). Three kinds of TCN composite photocatalysts were then prepared by recombining with amorphous TiO2 separately. All three photocatalysts were characterized by differnent methods, and their differences in photocatalytic reduction of Re(VII) were compared in detail. The experimental results show that U-TCN using urea as the N source has more uniform appearance, the largest specific surface area (474 m2/g), and the most excellent light absorption performance, leading to its photocatalytic reduction efficiency (90%) for Re (VII) being significantly higher than T-TCN (20%) and M-TCN (15%). Transient photocurrent and electrochemical impedance (EIS) analyses prove that U-TCN exhibits the highest efficiency of photo-generated electron/holes separation. Electron paramagnetic resonance spectroscopy (EPR) analysis shows that U-TCN generates more hydroxyl radicals (?OH), so that there are stronger reducing ?CO2 radicals produced by the reaction with formic acid, which is more conducive to the reduction of Re (VII). X-ray absorption spectra are employed to analyze the valence state and coordination environment of Ti element, which demonstrates an excellent photochemical stability of U-TCN. The study not only illustrates the effects of N sources on the photocatalytic performance of TCN composites, but also provides a promising photocatalyst for reduction and removal of Tc(VII) from waste water.

Key words: N sources, amorphous TiO2/g-C3N4 composites, photocatalytic reduction, Re(VII)/Tc(VII)

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