Titania Nanotubes Arrays Based-Gas Sensor: NO₂-Oxidizing Gas and H₂-Reducing Gas

Gas sensor based on titanium dioxide (TiO₂) nanotube was manufactured and its sensitivity to hydrogen (H₂) and to nitrogen dioxide (NO₂) gasses was investigated using anodization method.  The TiO₂ NT structure was studied using X-ray diffraction (XRD). The surface morphology of prepared Titania was analysed using field-emission electron-scanning microscopy (FE-SEM). Starting with (XRD) study it confirms the tetragonal phase structure of the prepared Titania (anatase and rutile). In addition, the TiO₂ anatase averaged crystallite size was 25.9 nm. The FE-SEM images revealed that the nanotube's average diameters are within 70 ± 2 nm. Gas response measurements at room temperature (27 ℃) for hydrogen and nitrogen dioxide gases at various concentrations (100, 150, 200, 250 and 300 ppm) were investigated. Our study has shown that the higher resistance of NO₂ gas was 30 Ω at 300 ppm while it was equal 18.29 Ω at 150 ppm for H₂ gas at room temperature.