Hydrothermal Synthesis and Photocatalytic Activity of Titanium Dioxide Nanotubes, Nanowires and Nanospheres
- PDF / 721,737 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 66 Downloads / 235 Views
1144-LL07-08
Hydrothermal Synthesis and Photocatalytic Activity of Titanium Dioxide Nanotubes, Nanowires and Nanospheres Jin Wang1, Ming Li1, Mingjia Zhi1, Ayyakkannu Manivannan2, Nianqiang Wu1,* 1
Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506-6106, USA 2 Department of Physics, West Virginia University, Morgantown, WV 26506, USA *Corresponding author: Fax: +1-(304)-293-6689, E-mail: [email protected] ABSTRACT TiO2 nanostructures with various morphologies and crystal structures were obtained by calcination of alkaline hydrothermal synthesized hydrogen titanate at different temperatures. The photocatalytic activities of the as-prepared samples were investigated by degradation of methyl orange aqueous solution under ultraviolet irradiation. The effects of the phase composition, crystallinity, surface area and shape of the nanostructures were evaluated. The results showed that high crystallinity, pure anatase phase and nanowire structure are favorable for the photocatalysis. The dependence of the photocatalytic activity on the surface area is not significant as usually expected. INTRODUCTION Titanium dioxide is widely used in photocatalytic and photoelectrochemical systems [1-2]. Recently, an alkaline hydrothermal method was demonstrated to be capable of scale-up production of one-dimensional (1-D) titanate nanostructures such as nanotubes and nanowires [3]. TiO2 nanotubes have a high specific surface area and an open mesoporous morphology, which are expected to facilitate the adsorption of reactants on the active surface sites [4]. For TiO2 nanowires, preliminary theoretical modeling and calculation work have showed that materials with such 1-D morphology may possess higher charge transport property as compared to nanospheres [5] The photocatalytic and photoelectrochemical performances of the catalyst materials are governed by several factors such as surface area, particle size, pore volume and distribution, crystal structure and phase composition, surface and bulk defects, impurity species, morphological structure as well as surface hydroxyl group and etc. [6-8]. Given the conflicting results from the previous studies on the photocatalysis of TiO2 materials, it remains unclear how these factors play their roles in the photocatalysis process. The inconsistency among the reported results mostly stems from the use of catalysts obtained from different synthesis routes, which leads to the difference in the specific surface properties of the products, such as defects concentration, crystallinity and etc. Thus the pivotal step toward better understanding the effects of the different parameters (particle size, phase composition and etc.) on the photocatalytic performance is to develop a synthesis route which is capable of producing TiO2 materials with controllable and repeatable properties (crystal structure, morphology, surface area and etc). The alkaline hydrothermal synthesis method is capable of tailoring TiO2 nanomaterials into different structures and shapes in a
Data Loading...
