High performance mixed potential type NO₂ sensors using porous yttria-stabilized zirconia (YSZ) layers doped with different concentration graphite as solid electrolyte and LaFeO₃ as sensing electrode were fabricated and characterized. LaFeO₃ was prepared by a typical citrate sol–gel method and characterized using XRD. The surface morphology and porosity of porous YSZ layers were characterized by field emission scanning electron microscope (FESEM). The sensor doped with 3 wt% graphite shows the highest response (−76.4 mV to 80 ppm NO₂) and the response is linearly dependent on the logarithm of NO₂ concentration in the range of 10–200 ppm. The sensor measurement results also present good repeatability and cross-sensitivity.

Mixed potential type ethanol gas sensor using Yttria-Stabilized Zirconia(YSZ)as solid electrolyte and LaFeO₃ as sensitive material was fabricated and characterized. LaFeO₃ was prepared by a sol-gel method and characterized by XRD.YSZ substrate and sensitive electrode were characterized using field emission scanning electron microscope. The measurement results show that the presented sensor exhibits a high sensitivity(135 mV to 400×10^-6 ethanol)and fast response time(14 s to 50×10^-6 ethanol)at 350 ℃. The results also demonstrate good repeatability and selectivity of the fabricated sensor.