PPB级锆基安培型NO气体传感器性能的研究

Characteristics Study of the Zirconia-Based Amperometric Gas Sensors Response to the PPB-Level Concentration of NO

采用丝网印刷技术制备了以In2O3为敏感电极的锆基安培型三电极NO传感器用以探测10-9级NO气体。用X射线衍射仪（XRD）和扫描电镜（SEM）对该传感器进行了理化分析;通过测量其在不同温度和不同NO浓度的气氛中的伏安特性曲线和时间响应曲线,研究了传感器的电流输出信号和NO浓度的关系以及时间响应特性。实验表明：在350℃~500℃测试温度范围内,极化电压为-60 m V,NO浓度变化为0~900×10-9时传感器响应电流的变化值Δcurrent和NO浓度之间存在较好的线性关系并且传感器在400℃时响应值最大。在被测气体总流量为100 cm3/min时,传感器信号90%的响应和恢复时间分别为18 s和12 s。传感器信号不受CO2浓度变化的影响,传感器的响应信号在测试时间里具有较好短期稳定性,但长期稳定性有待进一步提高。本文还采用阻抗谱分析方法对传感器的响应机理进行了初步的探索。

Amperometric NO sensor based on yttria-stabilized zirconia（YSZ）with In2O3 sensing electrode was pre-pared by screen-printing technique to detect the ppblevel of NO. The physical characteristics of the sensor werestudied by the X-ray diffraction（XRD）and scanning electron microscope（SEM）.The sensitivity of the sensor wasstudied by measuring the current-voltagecurves and response/recovery time characteristics atdifferent NO concentra-tions and temperatures.The results show that,inthe range of 350 ℃~500 ℃and with the polarization voltage of- 60 m V,there is a good linear relationship between the variation of the current change ？currentand NO concentration,whilethe volume fraction of NO changes from 0 to 900×10- 9.The sensor response best when the temperature is at400 ℃. When the total gas flow rate is 100 cm3/min,the response and recovery time of the 90% signal of the sensorsare respectively 18 s and 12 s. Sensor signal is not affected by changes in CO2concentration;the response signal ofthe sensor has good short-term stability during the test timebutlong-term stability needs to be further improved. Theresponse mechanism of the sensor has been explored by the AC impedance spectrum analysis method.