Metal-oxide sensors, detect gas through the reaction of surface oxygen molecules with target gases, are promising for the detection of toxic pollutant gases, combustible gases, and organic vapors; however, their sensitivity, selectivity, and long-term stability limit practical applications. Porous structure for increasing surface area, adding catalyst, and altering the operation temperature are proposed for enhancing the sensitivity and selectivity. Although humidity can significantly affect the property and stability of the sensors, studies focusing on the long-term stability of gas sensors are scarce. To reduce the effects of humidity, 1H, 1H, 2H, 2H–perfluorooctyltriethoxysilane (PFOTS) was coated on a porous SnO₂ film. The interconnected SnO₂ nanowires improved the high surface area, and the PFOTS coating provided superhydrophobicity at water contact angle of 159°and perfect water vapor repellency inside E-SEM. The superhydrophobic porous morphology was maintained under relative humidity of 99% and operating temperature of 300 °C. The CO gas sensing of 5, 20, and 50 ppm were obtained with linearity at various humidity. Flame detection was also achieved with practical high humidity conditions. These results suggest the simple way for reliable sensing of nanostructured metal-oxide gas sensors with high sensitivity and long-term stability even in highly humid environments.

中文翻译：

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降低湿度影响的自组装单层涂层多孔SnO2薄膜气体传感器

金属氧化物传感器可通过表面氧分子与目标气体的反应来检测气体，有望用于检测有毒污染物气体，可燃气体和有机蒸气。但是，它们的敏感性，选择性和长期稳定性限制了实际应用。为了提高灵敏度和选择性，提出了用于增加表面积，添加催化剂和改变操作温度的多孔结构。尽管湿度会显着影响传感器的性能和稳定性，但针对气体传感器的长期稳定性的研究却很少。为了减少湿度的影响，在多孔SnO ₂膜上涂覆了1H，1H，2H，2H-全氟辛基三乙氧基硅烷（PFOTS）。互连的SnO ₂纳米线改善了高表面积，并且PFOTS涂层在159°的水接触角下提供了超疏水性，并在E-SEM内部提供了良好的拒水性。超疏水多孔形态在相对湿度为99％和工作温度为300°C时保持。在各种湿度下，线性度分别为5、20和50 ppm的CO气体。在实际的高湿度条件下也可以实现火焰检测。这些结果表明即使在高度潮湿的环境中，也可以以高灵敏度和长期稳定性可靠地检测纳米结构金属氧化物气体传感器。