State Key Laboratory of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, People's Republic of China.
Nanoscale Res Lett. 2012 Apr 13;7(1):217. doi: 10.1186/1556-276X-7-217.
Three-dimensional (3D) TiO2 hierarchical structures with various microstructures have been successfully synthesized via a surfactant-free and single-step solvothermal route, in which hydrochloric acid (HCl), nitric acid (HNO3), and acetic acid (HAc) are employed as the acid medium, respectively. The effects of acid medium on the microstructures and properties of 3D TiO2 hierarchical structure have been studied. The results indicate that 3D dandelion-like microspheres assembled of radial rutile nanorods are obtained in the sample prepared with HCl. Both the fraction of rutile and the diameter of nanorod enhance with the increasing HCl concentration. For the products derived from either HNO3 or HAc, 3D spheres composed of anatase nanoparticles are present. The 3D dandelion-like TiO2 hierarchical structures show low reflectance and efficient light harvesting since this ordered rod geometry offers a light-transfer path for incident light as well as multiple reflective and scattering effects. Moreover, 3D TiO2 with this unique topology shows superior photocatalytic activity despite low surface area, which can be ascribed to the enhanced light harvesting, fast electron transport, and low electron/hole recombination loss.
通过无表面活性剂的一步溶剂热法成功合成了具有各种微观结构的三维（3D）TiO2 分级结构，其中分别使用盐酸（HCl）、硝酸（HNO3）和乙酸（HAc）作为酸介质。研究了酸介质对 3D TiO2 分级结构的微观结构和性能的影响。结果表明，在 HCl 制备的样品中得到了由径向金红石纳米棒组装的 3D 蒲公英状微球。随着 HCl 浓度的增加，金红石的分数和纳米棒的直径都增加。对于源自 HNO3 或 HAc 的产物，由锐钛矿纳米粒子组成的 3D 球体存在。3D 蒲公英状 TiO2 分级结构具有低反射率和高效的光捕获能力，因为这种有序的棒状几何形状为入射光提供了光传输路径以及多次反射和散射效应。此外，尽管表面积低，但具有这种独特拓扑结构的 3D TiO2 表现出优异的光催化活性，这可以归因于增强的光捕获、快速的电子输运以及低的电子/空穴复合损失。
