A Comparative Study on Photocatalytic Activity of Titania Nanowires Subjected to High-Temperature Calcination and Low-Temperature HCI Treatment

摘要

Titania thin films with ordered nanostructures offer combined advantages of high specific surface area and favorable charge separation, which are key points for efficient photocatalytic degradation of organic pollutants in water or atmosphere. In this paper, titania nanowire arrays were fabricated on titanium plates using a hydrogen peroxide solution, which were then subjected to a subsequent HCI treatment at a low temperature of 80 ℃ to achieve crystallized nanorod arrays. The nanorod array was characterized in detail by electron microscopy, X-ray diffraction, and various spectroscopic techniques, in comparison with the nanowire array after a high temperature calcination in air atmosphere to induce crystallization. The array efficiency in assisting photodegra-dation of rhodamine B in water under the UV-Vis irradiation was studied in relation to the relevant structural parameters. It is found that the low-temperature-deposited nanorod array exhibited a photocatalytic activity superior to that of the calcinated nanowire array. The enhanced efficiency has been attributed to the reduced band gap, a higher density of surface hydroxyl groups and the coexistence of anatase and rutile in the film.