Abstract:
Nano-porous titanium dioxide (TiO2) thin films were
developed by UV assisted potentiostatic anodization of
99.7% pure titanium foil. The internationally popular soft
drink Coca-Cola was used as the electrolyte in this
anodization process. Electrochemical oxidation and
photoetching were carried out at room temperature and at
10 V potentiostatic bias without and with 400 W UV light
illumination respectively. The prepared TiO2 thin film was
annealed at 150á´¼C for 3 hours. The surface of the prepared
TiO2 film was characterized with Scanning Electron
Microscopy (SEM) and Atomic Force Microscopy (AFM) to
confirm the crystallinity, porous structure and surface
roughness. The Optical study revealed a band gap of 3.898
eV. Hot probe method exhibited n-type conductivity of the
electrochemically grown TiO2 thin films. Palladium-Silver
alloy (Pd-Ag) contacts were deposited laterally on the oxide
surface as catalytic metal electrodes to fabricate a planar
sensor configuration. The hydrogen sensor study was
carried out at different temperatures (100 to 200á´¼C) and in
different hydrogen gas concentrations (1000 to 10000 ppm).
Nanocrystalline and nano-porous TiO2 sensor was
promising to sense hydrogen in air ambient with relatively
fast response and recovery times (e.g. ~2.9 s and ~75 s) at the
optimum temperature of 1500C. Brief mechanism behind the
sensing performance has been also discussed.