In-situ fabrication of ZnO nanoparticles sensors based on gas-sensing electrode for ppb-level H₂S detection at room temperature

The zinc oxide (ZnO) nanoparticles (NPs) sensors were prepared in-situ on the gas-sensing electrodes by a one-step simple sol-gel method for the detection of hydrogen sulfide (H₂S) gas. The sphere-like ZnO NPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), energy dispersive x-ray analysis (EDX), and their H₂S sensing performance were measured at room temperature. Testing results indicate that the ZnO NPs exhibit excellent response to H₂S gas at room temperature. The response value of the optimal sample to 750 ppb H₂S is 73.3%, the detection limit reaches to 30 ppb, and the response value is 7.5%. Furthermore, the effects of the calcining time and thickness of the film on the gas-sensing performance were investigated. Both calcining time and film thickness show a negative correlation with the H₂S sensing performance. The corresponding reaction mechanism of H₂S detection was also discussed. (paper)