Hydrothermal synthesis and their ethanol gas sensing performance of 3-dimensional hierarchical nano Pt/SnO₂

A hierarchical SnO₂ nanosheet structure was constructed by the hydrothermal method using hydrated stannous chloride and thiourea as raw materials. Then lysine was used as a coupling agent to load Pt nano quantum dots with different contents on the surface of the SnO₂ nanosheets. The composition, morphology and structure of Pt/SnO₂ were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and energy dispersive spectroscopy. The gas sensitivity of the Pt/SnO₂ and SnO₂ nanostructures were also studied in detail. Compared with the pure SnO₂ nanosheets, the 3-dimensional structured nano 2.0% Pt/SnO₂ (Pt: SnO₂ = 2.0%, wt%) exhibits a higher gas sensitivity to ethanol gas at 240 °C. The gas sensitivity to 100 ppm ethanol of hierarchical nano 2.0% Pt/SnO is 2.5 times higher than pure SnO₂ nanosheet, and the response time and recovery time are 4 s and 5 s, showing excellent response and recovery behavior. Meanwhile, the sensor also exhibits a lower detection limit of 0.272 ppm, as well as the excellent temperature and time stability. The higher gas sensitivity is contributed from the “spillover” effect of Pt nano quantum dots and the Schottky barrier at the heterojunctions of hierarchical Pt/SnO₂ nanostructures.