Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (02): 457-464.doi: 10.3866/PKU.WHXB201112081

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Photocatalytic Property and Reaction Mechanism of (Ni-Mo)/TiO2 Nano Thin Film Evaluated with Congo Red

LI Ai-Chang, LI Gui-Hua, ZHENG Yan, FENG Ling-Ling, ZHENG Yan-Jun   

  1. Faculty of Chemistry and Material Science, Langfang Teachers College, Langfang 065000, Hebei Province, P. R. China
  • Received:2011-09-16 Revised:2011-11-27 Published:2012-01-11
  • Contact: LI Ai-Chang
  • Supported by:

    The project was supported by the Science and Technology Project of Hebei Province, China (11276732).

Abstract: (Ni-Mo)/TiO2 composite thin films were prepared by composite electroplating at a constant current. The surface morphology, phase structure, and optical characteristics of the thin films were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectrum, and ultravioletvisible diffuse reflectance spectroscopy (UV-Vis DRS), respectively. The photocatalytic properties of the (Ni-Mo)/TiO2 composite thin films were evaluated with Congo red as a model compound. The effects of pH of the Congo red aqueous solution on the photocatalytic activity of the (Ni-Mo)/TiO2 thin films were investigated. Using cyclic voltammetry technique and a method of adding active species scavengers to the solution, the mechanisms of photocatalytic degradation of the films were explored. The results show that the (Ni-Mo)/TiO2 films consist of crystalline grains of TiO2 in the size range of 50-100 nm and nanocrystalline grains of Ni-Mo in solid solution. The (Ni-Mo)/TiO2 films are photocatalytically more active than a TiO2/ITO (indium tin oxide) reference film. Under halogen light irradiation, the photocatalytic degradation rate of the (Ni-Mo)/TiO2 films is 2.43 times as much as that of a porous TiO2 (Degussa P25)/ ITO film. The improvement in photocatalytic activity for the composite films could be mainly attributed to the heterojunction of (Ni-Mo)/TiO2, the electronic passageway of Ni-Mo in the composite films, and the catalysis of Ni-Mo in the composite film for the reaction of excited electrons with dissolved oxygen. The photocatalytic reaction mechanisms of the (Ni-Mo)/TiO2 films evaluated with Congo red are given under visible and UV light irradiation, respectively.

Key words: Photocatalysis, (Ni-Mo)/TiO2 nanofilm, Composite electroplating, Cogon red, Reaction mechanism