Study of NO2 sensors based on La0.8Sr0.2Co0.2Fe0.8O3-δ/Ag biphasic composite sensing electrodes

Abstract

In order to enhance the sensing performance of the NO2 sensor, La0.8Sr0.2Co0.2Fe0.8O3-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 NO2 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|, when θ is 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 using θ as 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 CH4, CO2, H2, CO and NH3. Therefore, the preparation of biphasic sensing electrode materials with a homogeneous distribution of the second phase and excellent catalytic activity by the self-demixing method effectively improves the sensitivity and selectivity of the sensor, which provides a new idea for the preparation of high-performance NO2 sensors.

Keywords

• electrochemistry; no2 sensor; self-demixing method; biphasic sensing electrodes; la0.8sr0.2co0.2fe0.8o3-δ; ag