基于La_(0.8)Sr_(0.2)Co_(0.2)Fe_(0.8)O_(3-δ)/Ag双相复合敏感电极的NO_(2)传感器研究

Study of NO_(2)sensors based on La_(0.8)Sr_(0.2)Co_(0.2)Fe_(0.8)O_(3-δ)/Ag biphasic composite sensing electrodes

为了提高NO_(2)传感器的敏感性能,采用自分相法制备La_(0.8)Sr_(0.2)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF)和LSCF+0.050Ag,LSCF+0.075Ag,LSCF+0.100Ag双相敏感电极,并以YSZ为固体电解质,制备阻抗谱型NO_(2)传感器,研究Ag的掺杂量对传感器性能的影响。结果表明,与Z',Z″,|Z|相比,θ作为响应信号时传感器的响应恢复时间更短、响应信号更稳定;以θ为响应信号,基于LSCF,LSCF+0.050Ag,LSCF+0.075Ag和LSCF+0.100Ag敏感电极的传感器在450℃最佳工作温度下的灵敏度分别为11.12°,11.28°,13.62°和9.56°/10,其中LSCF+0.075Ag表现出更高的灵敏度,表现出优异的重现性和长期稳定性;此外,传感器对CH_(4),CO_(2),H_(2),CO和NH_(3)表现出优异的抗干扰性能。因此,采用自分相法制备第二相分布均匀、催化活性优异的双相敏感电极材料,有效提升了传感器的灵敏度及选择性,可为高性能NO_(2)传感器的制备提供新思路。

In order to enhance the sensing performance of the NO_(2)sensor,La_(0.8)Sr_(0.2)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF)and LSCF+0.050Ag,LSCF+0.075Ag,LSCF+0.100Ag biphasic sensing electrodes were prepared by the self-demixing method,and the impedance spectrum type NO_(2)sensor was successfully prepared with YSZ as the solid electrolyte.The effect of Ag doping on the performance of the sensor was studied.The results show that compared with Z',Z″and|Z|,whenθis used as the response signal,the response recovery time of the sensor is shorter and the response signal is more stable.The resutts show that usingθas the response signal,the sensitivities of the sensors based on LSCF,LSCF+0.050Ag,LSCF+0.075Ag and LSCF+0.100Ag sensitive electrodes are 11.12°,11.28°,13.62°and 9.56°at the optimal operating temperature of 450℃,and the sensitivity of LSCF+0.075Ag is higher.The sensor also exhibits excellent reproducibility and long-term stability.In addition,the sensor shows excellent immunity to CH_(4),CO_(2),H_(2),CO and NH_(3).Therefore,the preparation of biphasic sensing electrode materials with a homogeneous distribution of the second phase and excellent catalytic activity by the selfdemixing method effectively improves the sensitivity and selectivity of the sensor,which provides a new idea for the preparation of high-performance NO_(2)sensors.