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-VisDRS)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50-100nmTiO2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80min后,复合薄膜光催化刚果红的降解率是多孔TiO2(DegussaP25)/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.
（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）FFiO2 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）FFiO2 films are photocatalytically more active than a TiOJITO （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.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2012年第2期457-464,共8页
Acta Physico-Chimica Sinica
基金
河北省科技支撑计划项目(11276732)资助~~
