Synthesis of composite La1.67Sr0.33NiO4–YSZ for a potentiometric NOx sensor by microwave-assisted complex-gel auto-combustion

This paper reports a facile microwave-assisted complex-gel auto-combustion method synthesis of La1.67Sr0.33NiO4 and YSZ composite powders and their utilization for the fabrication of high performance potentiometric NOx sensors. The synthesized composite powders with different YSZ concentrations (5 wt%, 10 wt% and 20 wt%) were characterized using Fourier transformed infrared (FTIR) spectrum and X-ray diffraction (XRD). The gas sensing property of the composites to NO was tested at temperatures ranging from 400 °C to 600 °C. The sensor fabricated with 10 wt% YSZ addition composite sensing electrode exhibited the biggest response (about 27 mV for 700 ppm NO) at 400 °C. Moreover, the response time and recovery time were within 4–18 s and 6–35 s, respectively. The enhanced gas sensing performance of the sensor to NO may be attributed to the larger superficial area of triple phase boundary. This work demonstrated that the simply synthesized La1.67Sr0.33NiO4 and YSZ composite powders can be effectively used for the fabrication of potentiometric NOx sensors.