微量Sn4 掺杂TiO2纳米纤维结构材料的两步法制备及光催化性能

Two-Steps Preparation and Photocatalytic Property of TiO2 Na-no-Structured Fibers with Trace Sn4 -Doped

摘要:

本文以脱脂棉花纤维为模板，利用浸渍-热转化两步法制备了具有中空结构的微量Sn4 离子(<0.050(at.)%)掺杂TiO2纳米纤维结构光催化材料(Sn4 /TiO2)；通过XRD、SEM、TEM、UV-Vis技术以及样品在300 W Hg灯和500 W Xe灯(模拟太阳光)下对MB溶液的光催化降解脱色对样品进行了表征。结果表明：利用两步法成功制备了中空结构的Sn4 /TiO2纳米纤维结构材料；掺入的微量Sn4 离子均匀分布于TiO2晶格中；TiO2中微量的Sn4 离子掺杂使TiO2的吸收边发生明显红移，对整个紫外-可见光吸收增强；在紫外、模拟太阳光下显示出好的光催化活性。重要的是在模拟太阳光下，Sn4 /TiO2-0.030(at.)%的光催化活性是TiO2的近4.5倍，而在紫外光下，仅为2.7倍。 Sn4 /TiO2良好的光催化性能主要归于少量Sn4 掺入使TiO2的结构多级化、TiO2价-导带间掺杂能级(DE)的形成以及TiO2晶格中活性中心的形成等因素。此外，对MB溶液在Sn4 /TiO2上的光催化降解脱色动力学行为进行了研究，结果表明：比较好的服从一级动力学行为。

Abstract:

TiO2 nano-structured fibers with trace Sn4 -doped (Sn4 /TiO2) were prepared via a dipping-thermal conversion method (called as two-steps method) by using absorbent cotton fiber as the template and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), resolution transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-Vis ) techniques. Under the irradiation of Hg and Xe lamps (Simulated sunlight), the degradation of methylene blue (MB) on the samples was used as the model reaction to investigate their photocatalytic property. The results show that Sn4 /TiO2 nano-structured fibers with trace Sn4 are prepared via the two-steps method, doped Sn4 ions are well-distributed in TiO2 lattice and make the absorption edge of TiO2 red-shift and remarkably increase the intensity of the light adsorption in the range of UV to visible. And under Hg and Xe lamps, as-prepared samples show good photocatalytic activity for the degradation of MB solution. It is important that the activity of the samples Sn4 /TiO2-0.030% is 4.5 times as TiO2 under Xe lamp (Simulated sunlight) but 2.7 times as TiO2 under Hg lamp (UV light). Good photocatalytic property of Sn4 /TiO2 can be ascribed to multi-structure and the increase of active centers of TiO2 material and doped energy level between valence and conduction bands of TiO2 due to doping Sn4 ions in TiO2. In addition, the photocatalytic degradation of MB solution follows first-order kinetic behavoir well on the samples.