钯氮共掺杂TiO2的制备与表征及其可见光催化活性

在空气气氛和N₂中热处理表面均匀分散有尿素和氯化钯的纳米管钛酸,制备了两个系列Pd/N共掺杂的TiO₂光催化剂,并对所得样品进行了X射线衍射、透射电镜、X射线光电子能谱、紫外-可见漫反射光谱、荧光光谱和电子自旋共振等表征.结果表明,焙烧气氛对样品的形貌、晶体结构、光谱吸收、生成的氧空位浓度和可见光光催化性能的影响很大,其中在空气气氛中制备的样品光催化性能优于在N₂中制备的样品.在可见光(λ≥420nm)照射下,以丙烯为模型污染物考察了样品的光催化活性,发现在空气中400℃下焙烧的样品具有最佳的可见光催化活性.另外,讨论了Pd/N共掺杂TiO₂光催化剂具有可见光响应的机理,认为掺杂的Pd/N元素和制备过程中生成的氧空位是影响可见光催化性能的重要因素.

Preparation and characterization of Pd/N codoped TiO2 photocatalysts with high visible light photocatalytic activity

Pd/N codoped TiO₂ photocatalysts were prepared by annealing nanotubular titanic acid, uniformly dispersed urea, and palladium chloride in air or nitrogen atmosphere. The resultant photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and electron spin resonance spectroscopy. The results showed that the calcination atmosphere played an important role in the morphology, crystal structure, spectral absorption, oxygen vacancy concentration, and visible light photocatalytic performance of the catalysts. The photocatalytic performance of samples calcined in an air atmosphere was better than those calcined in a nitrogen atmosphere. The visible light photocatalytic activity of the samples was investigated by monitoring the photocatalytic oxidation of propylene. It was found that the samples prepared at 400 ℃ in air possessed the highest photocatalytic activity under visible light irradiation (λ ≥ 420 nm). The mechanism of the visible light response of the Pd/N codoped TiO₂ photocatalysts was discussed in depth, and the origin of the visible light photocatalytic activity was attributed to both the elemental Pt/N dopants and the existence of oxygen vacancies.