Research on Preparation and Performance of a New Solid Electrolyte Based Nitrogen Oxides Sensor

As a major gas pollution source, nitrogen oxide (NOx, NO + NO2) poses a serious threat to the natural environment and human health. Therefore, it is imperative to develop high-efficiency detection equipment for in-situ detection of NOR. The emission sources of NOx are mainly industrial exhaust gas and automobile exhaust gas. The gas temperature is relatively high and the composition is relatively complicated. The solid electrolyte-based gas sensor can realize high selectivity and high sensitivity detection of NOx at high temperature. In this study, a Co3O4/Cr2O3/YSZ composite material was used as the sensing electrode (SE) and YSZ was used as the solid electrolyte to prepare the impedance type of NOx sensor. The sensor was characterized by XRD, SEM and EDX, and the NOx sensing performance at high temperature was systematically studied. The results show that the Co3O4/Cr2O3/YSZ sensing electrode with particle size of about 200 nm has a high specific surface area due to the loose and porous structure, which is conducive to gas diffusion and mass transfer. The sensor shows a good response-recovery characteristic to NOx, and the O-2 concentration has little influence on the sensor. In addition, the sensor shows good reproducibility, stability, and selectivity. In order to further apply the sensor to in-situ detection of NOx under high temperature, we successfully prepared a novel self heated sensor. The sensor shows good sensitivity characteristics, and the concentration detection range is 10 x 10(-6)-1500 x 10(-6). In addition, the self-heating sensor shows good reproducibility. This research will provide new ideas for in-situ detection of NOx gas at high temperature.

Automated summary

This study developed a solid electrolyte-based NOx gas sensor using a Co3O4/Cr2O3/YSZ composite material as the sensing electrode and YSZ as the solid electrolyte. The results showed that the sensor exhibited high selectivity, sensitivity, and good response-recovery characteristics with minimal influence from O2 concentration. In addition, a novel self-heating sensor was successfully prepared, which demonstrated good sensitivity and reproducibility.