Preparation of SiO2@Au@TiO2 core–shell nanostructures and their photocatalytic activities under visible light irradiation
Preparation of SiO2@Au@TiO2 core–shell nanostructures and their photocatalytic activities under visible light irradiation
复制标题
DOI：
10.1016/j.cej.2013.04.064
复制
发表时间：
2013-06
影响因子：
15.1
通讯作者：
Miaomiao Ye;Huihui Zhou;Tuqiao Zhang;Yiping Zhang;Yu Shao
中科院分区：
文献类型：
--
作者：
Miaomiao Ye;Huihui Zhou;Tuqiao Zhang;Yiping Zhang;Yu Shao
通过三步合成结合煅烧，成功合成了Au纳米粒子修饰量可调的SiO2@Au@TiO 2核壳结构。采用X射线粉末衍射（XRD）、透射电子显微镜（TEM）、扫描透射电子显微镜（STEM）、N2吸附-脱附、X射线光电子能谱（XPS）和紫外-可见漫反射光谱（UV-vis漫反射光谱）对样品进行了表征。在可见光照射下，以萘普生为降解物，考察了样品的光催化活性。结果表明，该核壳结构由平均直径为337 nm的SiO2核、表面吸附的可调含量的Au纳米粒子和平均厚度为7.0 nm的TiO 2外层组成。光催化实验表明，Au修饰量为0.1wt%的SiO2@Au@TiO 2核壳纳米结构（记为SiAuTi-2）具有最高的光催化活性，因为它具有合适的Au纳米颗粒修饰量，既能收集可见光能量，又能抑制自由激子的复合。为了实现催化剂的快速分离，将超顺磁性Fe 3 O 4核嵌入Au 2核壳结构中，在外加磁场作用下10 min内即可将其从水溶液中分离出来。
SiO2@Au@TiO2core–shell nanostructures with tunable decoration amount of Au nanoparticles have been successfully synthesized by combining three individual synthesis steps with calcination. The as-prepared samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), N2adsorption–desorption, X-ray photoelectron emission spectroscopy (XPS), and UV–vis diffuse reflectance spectroscopy. The photocatalytic activities of the samples were evaluated by photocatalytic degradation of naproxen in aqueous solution under visible light irradiation. Results show that the as-obtained core–shell nanostructure is composed of a SiO2core with an average diameter of ∼337 nm, tunable content of Au nanoparticles adsorbed on the surface of SiO2core, and an outer layer of TiO2with an average thickness of ∼7.0 nm. Photocatalysis experiments indicate that the SiO2@Au@TiO2core–shell nanostructures with Au decoration amount of 0.1 wt% (denotes as SiAuTi-2) exhibit the highest photocatalytic activity since it has the suitable decoration amount of Au nanoparticles for harvesting the visible-light energy and for prohibiting the recombination of free excitons. For fast separation of the catalysts, superparamagnetic cores of Fe3O4were embedded in the SiO2@Au@TiO2core–shell nanostructures and hence they can be separated from aqueous solution by an external magnetic field within 10 min.