Effect of Al2O3-SiO2 substrate on gas-sensing properties of TiO2 based lambda sensor at high temperature

Alumina is widely used as substrate material for oxygen lambda sensors. It has been reported that response properties of sensors are highly dependent on surface state of substrates. In this work, Al2O3-x%SiO2 (x = 2-30) substrates were specially prepared for TiO2 based lambda sensors for high temperature operation. Structure and surface state of prepared substrates were characterized by XRD, SEM and XPS. TiO2 sensing film was prepared by screen printing method. Results indicated that sensors fabricated on Al2O3-10%SiO2 substrate exhibited the best sensing properties. Moreover, final steady-state voltages of all sensors were limited to less than 100 mV at 600-800 ℃.