Improvement of the oxygen gas sensitivity in doped TiO2 thick films

Abstract The titania (TiO2) thick films were prepared by using screen-printing technology of 0.00, 0.20 and 0.40 wt.% Nb and 0.40 wt.% Cr concentration on alumina substrate. These thick films were sintered at 1300°C for 5 h in the atmosphere to obtain rutile phase of TiO2. The material characterization was done by using X-ray diffraction (XRD) and scanning electron microscope (SEM). The sensitivity measurements were carried out as a function of operating temperature (400–600°C) in Nb doped TiO2 sensor and (600–800°C) in Cr doped sensor as a function of oxygen partial pressure. The response time measurements in Nb doped sensors were carried out at operating temperatures (400–600°C) at 1200 ppm oxygen partial pressure and operating temperatures (600–800°C) at 1000 ppm oxygen partial pressure in Cr doped TiO2 sensor. The results show that Nb doped sensor exhibits higher sensitivity at 550°C as compared to pure TiO2 sensor, while in the other case, Cr doped sensor shows high sensitivity towards oxygen at 700°C. The result indicates that grain growth cab can be modified by using suitable doping which is responsible for improving stability and sensitivity of the sensor.