物理化学学报 >> 2012, Vol. 28 >> Issue (02): 457-464.doi: 10.3866/PKU.WHXB201112081

催化和表面科学 上一篇    下一篇

(Ni-Mo)/TiO2纳米薄膜光催化降解刚果红的性能与机理

李爱昌, 李桂花, 郑琰, 冯玲玲, 郑彦俊   

  1. 廊坊师范学院化学与材料科学学院, 河北廊坊 065000
  • 收稿日期:2011-09-16 修回日期:2011-11-27 发布日期:2012-01-11
  • 通讯作者: 李爱昌 E-mail:aichangli@hotmail.com
  • 基金资助:

    河北省科技支撑计划项目(11276732)资助

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 E-mail:aichangli@hotmail.com
  • Supported by:

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

摘要: 用恒电流复合电沉积方法制备(Ni-Mo)/TiO2薄膜, 以扫描电子显微镜(SEM)、X 射线衍射(XRD)、拉曼(Raman)光谱和紫外-可见漫反射光谱(UV-Vis DRS)对薄膜的表面形貌、晶相结构和光谱特性进行了表征, 以刚果红为模拟污染物对薄膜的光催化性能进行了测定, 并讨论了刚果红溶液的pH值对薄膜光催化活性的影响. 采用循环伏安技术和向溶液中加入活性物种捕获剂的方法对薄膜光催化降解机理进行了探索. 结果表明:(Ni-Mo)/TiO2薄膜是由粒径为50-100 nm TiO2纳米粒子相和纳米晶Ni-Mo 固溶体相构成的复合薄膜. 薄膜具有较高的光催化活性, 卤钨灯照射80 min 后, 复合薄膜光催化刚果红的降解率是多孔TiO2 (Degussa P25)/ITO(氧化铟锡)纳米薄膜的2.43 倍. (Ni-Mo)/TiO2 薄膜光催化活性的提高主要归因于薄膜层中有效形成的(Ni-Mo)/TiO2异质结和良好的电子通道, 以及Ni-Mo 纳米晶合金对溶解氧和激发电子还原反应的催化作用. 分别给出了在紫外和可见光下薄膜光催化降解刚果红的反应机理.

关键词: 光催化, (Ni-Mo)/TiO2纳米膜, 复合电沉积, 刚果红, 反应机理

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

MSC2000: 

  • O643