High-performance hydrogen gas sensor based on Ag-incorporated ZnO nanoparticles

ZnO-based sensors often suffer from low response rates and long response and recovery times. To address this issue, Ag-incorporated ZnO-based gas sensors with Ag contents of 2, 4, 6, and 8% were synthesized using a simple, fast, and cost-effective method, making them promising candidates for future industrial applications. Structural analysis confirmed the presence of Zn–O bonding and the incorporation of silver as a secondary metallic phase, well integrated with the ZnO nanoparticles. Gas sensing tests were performed under different conditions, and the sample with 2% Ag content exhibited an extraordinary response of 4357%, approximately 29 times higher than that of pure ZnO nanoparticles. The sample with 8% Ag content showed the lowest response and recovery times. Additionally, the response rates of the samples were positively correlated with both concentration and temperature. The increase in response rate was attributed to the spill-over effect in the samples, which enhanced hydrogen mobility. The results demonstrated that Ag-doped ZnO nanoparticles exhibited higher porosity compared to the pure ZnO sample. This suggests that tuning the porosity or structure can further enhance the performance of ZnO-based sensors. Moreover, the fabricated sensor showed high sensitivity and an exceptionally low detection limit, indicating strong potential for the continued development of ZnO nanostructure-based gas sensors.