基于Na_3Zr_2Si_2PO_(12)固体电解质的非平衡态SO_2传感器

SO_2 Non-equilibrium Gas Sensor Based on Na_3Zr_2Si_2PO_(12) Solid Electrolyte

基于Na_3Zr_2Si_2PO_(12)(NASICON)固体电解质,分别以Na_2SO_4-BaSO_4混合盐和NaRe(SO_4)_2复盐为敏感电极材料制备了片式SO_2非平衡态气体传感器。结果表明,该类型传感器的输出电动势与SO_2气体浓度的对数呈良好的线性关系,在低温260℃具有最佳性能,灵敏度分别达到了160 m V/decade和136 m V/decade。传感器在不同浓度的SO_2气体中的交流阻抗谱测试结果显示,气体在敏感电极的三相界面处电化学反应的活性随着气体浓度的增大而增强,结合敏感电极结构,对该类敏感电极的机理进行了分析。由于NASICON具有良好的低温钠离子导电性,可以大幅降低传感器的工作温度;由于Na_2SO_4-BaSO_4混合盐和Na Re(SO_4)_2敏感材料具有更好的化学稳定性,制备的传感器具有良好的可重复性和稳定性。基于非平衡态设计的传感器,具有结构简单和成本低的优点。以上特性为该传感器在SO_2气体在环境监测方面的应用提供了可能。

This paper reported fabrication and sensing properties of solid-state gas electrochemical sensors for sulfur dioxide based on a non-equilibrium working mechanism. Based on Na3Zr2Si2PO12（NASICON） solid electrolyte, SO2 non-equilibrium gas sensors were fabricated by using Na2SO4-BaSO4 mixture and NaRe（SO4）2 as sensing electrodes. The results showed that there was a good linear relationship between the logarithm of SO2 gas concentration and the sensor output electric potential value. Working at low temperature of 260℃, the sensors display best performances, with sensitivity up to 160 mV/decade and 136 mV/decade. Furthermore, the devices has good repeatability and stability. AC impedance of the sensors in different concentrations of SO2 gas reveals that the electrochemical activity at three phase boundary （TPB） rised with the increased SO2 concentration. Working temperature of the prepared sensor is obviously decreased which is benefited from the high Na＋ conductivity of NASICON at low temperature. The sensor possesses good stability and repeatability due to its high chemical stability of Na2SO4-BaSO4 mixture and NaRe（SO4）2 as sensing materials. The sensor based on non-equilibrium mechanism has many advantages, such as low-cost and simple structure. Owing to the above features, the sensor can be possibly applied in the environment monitoring of SO2.