TiO2−x thin films as oxygen sensor

The TiO2 films are prepared by sol–gel method. The tetrabutyl titanate and absolute ethanol are used as raw material and solvent, respectively. Some stabilizing agents are added in the solution to obtain stable sols. By dip-coating, drying, preheating, the TiO2 films on Al2O3 substrates are formed. Then the TiO2−x films are obtained after reducing the TiO2 films in H2 atmosphere at 1000°C. The value of x determined by X-ray diffraction (XRD) is between 0 and 0.5. The experiment results show that the TiO2−x films have good oxygen sensitivity and reproducibility when tested in oxidizing–reducing atmosphere at 800°C and excellent resistance–temperature stability in N2 atmosphere.