TiO_2 Nanotube Arrays Prepared by Electrochemical Anodization: Influence of Anodization Conditions on Structure and Photocatalytic Activities

摘要

In this work, the highly-ordered TiO_2 nanotube arrays (TNAs) were fabricated by electrochemical anodization of Ti foils, and the influence of the anodization conditions (i.e., anodization voltage and time) on the structural morphologies and photocatalytic activities of the as-prepared TNAs was explored. From the experimental results, it was demonstrated that the applied anodization voltage and time had a significant impact on the structure of TNAs, and thus in turn on their photocatalytic activities. With the increase of the anodization voltage, the pore diameter of TNAs increased, and their corresponding photocatalytic activities also improved. The enhanced photocatalytic properties could be attributed to the enhanced pore diameter of TNAs, which could provide a higher specific surface area, a higher adsorption ability and a higher ability of generating photoinduced electron-hole pairs of active sites. On the other hand, with the increase of the anodization time, the pore diameter of TNAs decreased and the tube-wall thickness increased, whereas the photocatalytic activities decreased. The decreased photocatalytic performance could be ascribed to the decrease of the specific surface area and the adsorption capacity of the as-prepared TNA sample as a result from the decreased pore diameter and the increased tube-wall thickness of the TNA sample.