HIGHLY SELECTIVE NO2 GAS SENSOR OPERATING AT ROOM TEMPERATURE WITH PPB-LEVEL DETECTION SENSITIVITY BASED ON ZnO NANOPARTICLES

Abstract

In this work, authors reported a high-selectivity nitrogen dioxide (NO2) gas sensor that operates directly at room temperature without catalyst or illumination. The NO2 gas sensor was based on ZnO nanoparticles, which were synthesized using a simple solution method, ensuring scalability in mass production. Crucially, the sensor exhibited high sensitivity and selectivity towards NO2, achieving parts-per-billion (ppb) level detection limits. At 23°C, the sensor showed a sensitivity of 4.2% with the response time and recovery time are 120 s and 185 s, respectively, under 5 ppb NO2, while the interaction with other gases such as H2S, NH3, SO2, CH4, C3H8, and CO2 was negligible. This room-temperature, easily fabricated sensor offered a promising solution for cost-effective, real-time NO2 monitoring in various applications, particularly those requiring high sensitivity at low NO2 concentrations.