Open Access Nano Express

Effects of acid on the microstructures and properties of three-dimensional TiO2 hierarchical structures by solvothermal method

Jing Zhou13, Bin Song2*, Gaoling Zhao1* and Gaorong Han1

Author Affiliations

1 State Key Laboratory of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, People's Republic of China

2 Department of Physics, Zhejiang University, Hangzhou, 310027, People's Republic of China

3 , Zhejiang Police College, Hangzhou, 310053, People's Republic of China

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Nanoscale Research Letters 2012, 7:217  doi:10.1186/1556-276X-7-217

Published: 13 April 2012

Abstract

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.

Keywords:
Three-dimensional; TiO2; Acid; Solvothermal; Optical properties; Photocatalytic activity; 60; 61.46.Km; 62.23.St