High sensitivity and recoverable SnO₂-based sensor promoted with Fe₂O₃ and ZnO for sub-ppm H₂S detection

A SnO₂-based thick film gas sensor promoted with Fe₂O₃ and ZnO (SnFeZn) was developed in this study for the detection of 1 ppm H₂S gas at 350 °C. The SnFeZn was prepared by physical mixing of SnO₂ with Fe₂O₃ and ZnO. The SnFeZn sensor showed not only a high response of about 4.5, but also complete recovery on detection of H₂S. Moreover, the response of SnFeZn sensor was maintained during multiple cycles of detection and recovery without deactivation, unlike the response magnitude of a SnO₂ sensor. These results were due to the effect of the Fe₂O₃ and ZnO promoters. The Fe₂O₃ promoter played an important role in the improvement of sensor recovery, and the ZnO promoter played an important role in the enhancement of sensor response.