(Ni-Mo)-TiO2纳米薄膜的制备及其光催化降解罗丹明B的性能

以恒电流复合电沉积方法制备(Ni-Mo)-TiO2薄膜。采用SEM、XRD和DRS对薄膜的表面形貌、相结构和光谱特性进行表征,以罗丹明B为模拟污染物对薄膜的光催化活性进行测定,讨论罗丹明B溶液的pH值、通入气体以及不同辐射光波对薄膜光催化性能的影响,并推测光催化机理。结果表明:(Ni-Mo)-TiO2薄膜是由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,在可见光和紫外光照射下,罗丹明B的降解率分别为多孔P25 TiO2粒子薄膜的2.0倍和1.7倍。复合薄膜光催化活性的提高主要源于在薄膜层中能有效形成(Ni-Mo)/TiO2异质结和良好的电子通道,它一方面可以促使光生电荷的分离,另一方面加速了氧气与激发电子的还原反应。

Preparation of (Ni-Mo)-TiO2 thin films and their photocatalytic activity of Rhodamine B

The(Ni-Mo)-TiO2 thin film was prepared by electrolytic co-deposition of Ni-Mo ally and TiO2 particles from a solution in which TiO2 nano particles(P25) were suspended by stirring.The surface morphology,phase structure and optical characteristics of the thin film were analyzed by scanning electron microscopy(SEM),X-ray diffractometry(XRD) and diffuse reflectance ultraviolet-visible spectroscopy(DRS),respectively.The photocatalytic properties were evaluated with Rhodamine B as a model compound.The effects of pH of the Rhodamine B aqueous solution,gaes bubbling through the solution,UV and visible light irradiation on the photocatalytic activity of(Ni-Mo)-TiO2 thin film were investigated.And the photocatalytic reaction mechanism was presumed.The results show that the(Ni-Mo)-TiO2 thin film consists of TiO2 crystalline particles in the size of 50-100nm and Ni-Mo nano crystalline in solid solution.The(Ni-Mo)-TiO2 film is photocatalytically more active than that of TiO2/ITO.Under visible and UV light irradiation,the photocatalytic degradation rate of(Ni-Mo)-TiO2 film is 2.0 times and 1.7 times as much as that of the TiO2/ITO thin film,respectively.The increasing photocatalytic activity is mainly due to the heterojunction of(Ni-Mo)/TiO2 and good electronic passage-way in the film,both of which can efficiently promote the separation of charges and accelerate the reaction of excited electrons with oxygen relatively to TiO2/ITO film in photocatalytic degradation for Rhodamine B.