Sensitivity Enhancement of Yttria-Stabilized Zirconia-Based Mixed-Potential NO2 Sensors via the Optimization of LaCrO3 Particle Size and Distribution

The use of NO 2 sensors is a significant measure for reducing NO 2 emissions from industrial plants and vehicles. The performance of these devices considerably depends on the morphology of sensing electrodes, which in turn is directly influenced by the particle size of the raw powder used for gas detection. In this study, the particle size distribution (PSD) of LaCrO 3 powder was optimized through adjustments to calcination temperature, and the influence of such optimization on the morphology of sensing electrodes was considered in the examination of sensing performance. The results indicated that the sensor (S300) fabricated with the optimally calcined powder exhibited the best performance, achieving a high sensitivity of 52.52   mV/decade and a low limit of detection of 16.5 ppb—advantages stemming from the optimized gas diffusion pathways and triple phase boundaries (TPBs) in the sensing electrodes. The sensor also exhibits excellent selectivity, repeatability, and long-term stability. Overall, the PSD-oriented method developed in this research serves as an effective strategy for designing mixed-potential sensors, showing promising applications in high-temperature exhaust gas monitoring.