Investigation on mixed potential NO_2 sensor based on nano-structured CuO sensing electrode

A mixed potential NO2 sensor was fabricated by using yttria-stabilized zirconia(YSZ) electrolyte and nano-structured CuO sensing electrode(SE) prepared by sputtering method.The composition and microstructure of the CuO sensing electrode were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM),respectively.The impact of sputtering time on the microstructure of CuO and the sensitivity of the sensor was studied.The results showed that with the increasing sputtering time,the CuO particle size increased.The sensors showed good sensitivity to 25-400mL/m3 NO2 and the response signals of the sensors were linearly dependent on the logarithm of NO2 concentrations in the temperature range of 600-700℃.The sensitivity of the 60min-Cu sensor was up to 41.47mV/decade at 650℃.The 90% response and recovery time of the sensor were 160 and 260s,respectively operating at 650℃,400mL/m3 NO2.The response was slightly affected by changing CO2 concentrations in the range of 0-10vol%.The sensor showed good response,recovery,reproducibility and stability.