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

The properties of sensors manufactured by pressing BaSnO3 and BaSnO3 with Al2O3 were studied. An impact of Al2O3 on sensitivity and stability of sensors was established. The results show that an addition of Al2O3 to BaSnO3 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 BaSnO3 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 H2 is achieved by pressing BaSnO3 with 25 wt.% content of Al2O3, while to benzene vapour for BaSnO3 with 50 wt.% content of Al2O3.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.