The properties of barium stannate and aluminum oxide-based gas sensor: The role of Al2O3 in this system

Abstract The properties of sensors manufactured by pressing BaSnO 3 and BaSnO 3 with Al 2 O 3 were studied. An impact of Al 2 O 3 on sensitivity and stability of sensors was established. The results show that an addition of Al 2 O 3 to BaSnO 3 improves the mechanical strength, stability and sensitivity of sensors. Moreover, the decrease in the temperature of maximum sensitivity is observed. There is a broad sensitivity maximum at the temperature 550 °C, while in the case of BaSnO 3 sensors this temperature is above 700 °C. The optimum concentration of aluminum oxide in sensors depends on the kind detected gas. The best performance of sensors to CO and H 2 is achieved by pressing BaSnO 3 with 25 wt.% content of Al 2 O 3 , while to benzene vapour for BaSnO 3 with 50 wt.% content of Al 2 O 3 . We assume that the improvement of sensing properties of sensors based on barium stannate and a mixture of aluminum oxide is strongly connected with an increase in the adsorption of oxygen and detected gas.