Preparation and gas-sensing property of a nanosized titania thin film towards alcohol gases

Anatase phase TiO2 thin films were prepared by dip-coating technique. Atomic force microscope (AFM), X-ray diffractometer (XRD), FT-IR and UV–vis spectra were used for the structural characterization of the TiO2 films. The results showed that the titania particle was in anatase phase. The FT-IR spectrum exhibited a strong absorption peak at 631 cm−1 which was ascribable to the Ti–O vibration of the anatase phase. The AFM image of the thin films revealed the formation of a uniform but highly porous structure having mean particle size of about 14.89 nm. The results of UV–vis spectra indicated that each coated film could be well transmitted to the substrate. The sensing properties of TiO2 films were tested to methanol, ethanol and n-propanol at room temperature. The thin films exhibited high response to these gases. When the gas concentration was 10 ppm, the response was 2.6, 2.0 and 7.5 to methanol, ethanol and n-propanol, respectively. The films could detect as low as 3 ppm n-propanol, 10 ppm methanol and 10 ppm ethanol. The response and recovery time were within 1 min and 80 s, respectively.