Facile Fabrication of TiO2 Nanorod Arrays for Gas Sensing using Double-Layered Anodic Oxidation Method

Abstract

Self-organized anodic titanium dioxide nanorod arrays were fabricated using a two-stage anodization method from superimposed Ti-Al layers deposited on quartz substrates. The morphology of nanorods could be controlled by the anodizing conditions of the aluminum (first stage) and the titanium layer (second stage). The first stage of anodization process controls the diameter and density of nanorods and the second stage of anodization controls the height of nanorods. Therefore, we could fabricate nanorod arrays with desired aspect ratio and density under specific anodizing conditions. Furthermore, we used TiO2 nanorod arrays as the field ionization anode of a gas sensor, and the morphology of nanorods has shown to have a high correlation with the working voltage of gas sensing. The TiO2 nanorods possess good selectivity and low working voltage under different atmosphere and their working electric field is lower than gas sensing using carbon nanotubes and ZnO nanowires as the anode. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.013201jes].