Synthesis and H2S gas-sensing properties of SnO2/ZnO core/shell structure ☆

In this study, SnO2/ZnO core/shell nanowires were synthesized through the two-step processes. First, SnO2-core nanowires were synthesized from Sn powder source at 750 oC by a chemical vapor deposition method (CVD). The ZnO shell was then deposited on SnO2 nanowires by a DC sputtering method. The morphological and crystal structures of the grown SnO2/ZnO core/shell nanostructures were investigated by emission scanning electron microscopy (SEM), field-emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD). The results indicated a successful synthesis of the SnO2/ZnO core/shell nanowires with the thickness of the ZnO shell ranging from 5 nm, 10 nm, and 15 nm. The H2S gas sensing properties of the SnO2/ZnO core/shell structure sensors were then investigated, and results pointed out that the sample with a shell thickness of 10 nm showed an effective response and recovery to (0.25 ppm – 2.5 ppm) at the temperature range of 300 oC, 350 oC, 400 oC. The optimal working temperature of the sensor was found at 350 oC, where the sensor has a response of 7.8 towards 2.5 ppm. The selectivity of the sensor at 350 oC was also studied. These findings suggest that the sensor could have potential applications in detecting traces of H2S gas in the medical, food, and environmental fields.