Optimizing NO2 2 gas sensor performance: Investigating the influence of cobalt doping on WO3 3 recovery kinetics for enhanced gas sensing application

Gas sensors utilizing a chemiresistive metal oxide semiconductor (MOS) are extensively employed, particularly for detecting nitrogen dioxide (NO2) 2 ) at moderate temperatures. However, the gas response and the recovery time are hindering the performance of the MOS. In this research, to enhance the gas response and the recovery time a systematic investigation was performed to explore the impact of cobalt (Co) doping in tungsten trioxide (WO3) 3 ) and its gas sensing properties. Fascinatingly, the 3 mM% Co-doped WO3 3 sensor exhibits a remarkable gas sensing response of 20776 % at 10 ppm NO2, 2 , showcasing a seven-fold enhancement compared to the pristine WO3 3 sample at 200 degree celsius. The findings demonstrated that the sensor exhibited an outstanding repeatability, selectivity and long-term stability of 95 % over 8 weeks. Moreover, the sensor possessed a fast response and recovery time 15 s/23 s as compared to the pristine sensor 26 s/154 s. The exceptional gas-sensing capabilities can be ascribed to the existence of defects (oxygen vacancy) within the structure. These defects effectively boost the surface reactivity of WO3 3 nanoplates, thereby augmenting their sensitivity and enabling a broad-range sensing performance. As a result, this research demonstrates considerable promise for utilizing environmental NO2 2 monitoring applications.