Ag@AgI/Ni薄膜的制备及其模拟太阳光催化性能

采用电化学方法制备Ag@AgI/Ni表面等离子体薄膜催化剂，使用扫描电镜（SEM），X射线衍射（XRD）和紫外-可见漫反射光谱（UV-Vis DRS）对薄膜的表面形貌、晶体结构、光谱特性以及能带结构进行分析表征，在模拟太阳光照射下，把罗丹明B作为模拟污染物对薄膜的光催化活性与稳定性进行评价，采用向反应体系中加入活性物种捕获剂的方法对薄膜光催化机理进行探究。结果表明：最佳工艺下制备的Ag@AgI/Ni薄膜表面是由附着少量Ag粒子的AgI纳米晶构成。薄膜具有显著的表面等离子共振作用、优异的光催化活性和突出的光催化稳定性。光催化反应60 min，薄膜对罗丹明B的降解率（81.1%）是AgI/Ni薄膜的1.35倍，是TiO₂（P25）/ITO薄膜的1.61倍。在薄膜光催化活性基本保持不变的前提下可循环使用5次。薄膜表面纳米Ag的等离子共振对光阴极反应的活化是光催化性能提高的重要原因。提出了薄膜光催化降解罗丹明B的反应机理。

Ag@AgI/Ni Thin Films: Preparation and Photocatalytic Properties Under Simulated Solar Irradiation

Ag@AgI/Ni thin films plasmonic photocatalyst were prepared by electrochemical method. The surface morphology, phase structure, optical characteristics and band structure of the thin film were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), respectively. Its photocatalytic properties and stability were evaluated with rhodamine B(RhB) as a model compound under the simulated solar irradiation. Using a method of adding active species scavenger to the solution, mechanism of photocatalytic degradation of the films was explored. The Ag@AgI/Ni thin films prepared under the optimized preparation conditions are composed of AgI micron-sized particles coated with Ag nanocrystals, which have a significant surface plasmon resonance (SPR) effect. The thin film exhibits a maximum photocatalytic activity and a superior photocatalytic stability to decompose RhB. The photodegradation rate of the Ag@AgI/Ni thin films under the simulated solar irradiation 60 min (i.e., 81.1%) is 1.35 times greater than that of AgI/Ni thin film, and 1.61 times greater than that of P25TiO₂/ITO thin film. The photocatalytic activity almost keeps unchanged after five recycled experiments. The improvement in photocatalytic activity for Ag@AgI/Ni thin film can be mainly attributed to the activation of nano Ag particles on the film for photocathode reaction with a significant SPR effects. In addition, the photodegradation mechanism of the films for RhB under the simulated solar irradiation was also discussed.