Facile Fabrication of TiO₂Nanorod 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.

A baseball-bat-like CdTe/TiO2 nanorods-based heterojunction core–shell solar cell

“…In recent years, TiO 2 (titanium dioxide) structures have attracted much attention because of their potential applications in various areas, such as solar cells [1], photo-electrochemical hydrogen production [2], field emission devices [3] and gas detectors [4]. However, TiO 2 nanorod (NR) based solar cells have become particularly interesting for enabling the production of highly efficient solar cells in a cost-effective way.…”

Synthesis of Nanostructure TiO2 Nanorod Array on FTO Substrate using Hydrothermal Method and its Photocatalytic Activity

“…The hole reacted with water or adsorbed water to produce hydroxyl radical •OH as reaction (1)- (3). The electron also reacts with dissolved oxygen to form superoxide radical in reaction (4) as well as both electron and holes are reacting with adsorbed organic compound on semiconductor surface cause oxidation and reduction reaction as mention in reaction (5)- (6). The photodegradation experimental results indicate that the photocatalytic activity of the hydrothermally grown TiO2 NRA was found up to 47% in 180 min in an aqueous media [12].…”

“…The one-dimensional TiO2 nanostructure such as nanorod array and nanotubes grown vertically on substrate have received considerable attention due to its higher surface to volume ratio, large number of active site and surface defects favorable for photocatalytic application [1][2][3] . The nanostructures of TiO2 have variety of application in water splitting, photodetector, dye sensitized solar cell, gas sensor and photocatalytic degradation of organic compounds [4][5][6][7][8] . Currently, vertically aligned single crystal rutile TiO2 nanorod array grown on substrate have a considerable interest due to its ability to suppress electron and hole recombination than polycrystalline TiO2 which is useful in dye sensitized solar cell, photodetector, photocatalyst and water splitting [9,10] .…”

Hierarchical decoration of anodic TiO2 nanorods for enhanced photocatalytic degradation properties

“…The synthesis of rod or dot-like nanostructures from bilayers has been reported for a number of transition metal elements including Ti [8][9][10] and Ta [11]. In all cases, an initial nanoporous aluminum oxide template is formed by anodization in acidic solution until it reaches the interface ( Fig.…”

“…1(d)). TiO 2 nanorods formed by the anodization of Ti with an Al overlayer have found application in the control of cell growth [14][15][16], gas sensing [9], and field emission devices [17,18]. However, these nanostructures have not been exploited for photocatalytic applications; in particular, the structure of the as-grown rods is not well known, and the possibility to obtain the catalytically active anatase phase through phase transformation using thermal annealing is not well understood.…”