Effect of sintering temperature of mixed potential sensor Pt/YSZ/LaFeO3 on gas sensing performance

Gas-sensing performance of the electrochemical sensor utilized solid electrolyte of yttria-stabilized zirconia (YSZ) and metal-oxide sensing-electrode (SE) depends on electrochemical catalytic reaction at interface of metal-oxide/YSZ and heterogeneous gas-phase reaction through SE oxide. In this work, the mixed potential sensors with a configuration of Pt/YSZ/(Pt-LaFeO3) sintered at the temperatures Ts = 700, 800, 900, 1050, 1200 and 1300 °C were investigated by exposing to various gases such as NO2, NO, CO, C3H8 and CH4 at the operating temperatures To = 450, 500, 550, 600 and 650 °C. All the sensors Pt/YSZ/(Pt-LaFeO3) exhibited good sensitive and selective characteristics to NO2 gas. Interesting characteristics on the gas sensing performances were obvious that the ΔV responses to NO2 gas obtained the minimum and maximum values when the sensors Pt/YSZ/(Pt-LaFeO3) sintered at the temperatures Ts = 900 and 1200 °C, respectively. Typically, the sensors exhibited decrease of NO2 selectivity with increasing the sintering temperature Ts. The t90 response-recovery times of the sensors were relatively complicated with the sintering temperature. Effect of the sintering temperatures of the Pt/YSZ/LaFeO3 sensors on the gas sensing performances was also discussed in detail.