Hydrogen sensors, working at low temperatures while highly sensitive to low hydrogen concentrations, are essential, due to the low autoignition temperature, flammability and high explosibility of hydrogen. In this work, we report hydrogen sensors based on Pt-decorated WO₃, which are coated with SiO₂ membranes to decrease the working temperature and improve the selectivity and sensitivity. SiO₂ is deposited in-situ by chemical vapor deposition (CVD). The SiO₂ membrane enables the Pt-decorated WO₃ sensor a low working temperature of 150 °C, and an ultra-high sensitivity, i.e. a response of 100,000 towards 150 ppm H₂. In contrast, the sensor without the SiO₂ membrane shows a response of only 400 towards 150 ppm. The outstanding properties can be attributed to the low diffusion rate of oxygen in the SiO₂ membrane, which results in little oxygen absorption on the WO₃ surfaces. In addition, the SiO₂ membrane also contributes high selectivity to hydrogen. This work lays down the foundation for engineering ultra-sensitive and highly selective gas sensors. Beyond the particular WO₃ material, this work could also be a benefit to boost performances of hydrogen sensors based on other materials.

由于自燃温度低，氢的易燃性和高爆炸性，氢传感器在低温下工作时对低氢浓度高度敏感，因此必不可少。在这项工作中，我们报告了基于Pt装饰的WO _3的氢传感器，该传感器涂有SiO ₂膜以降低工作温度并提高选择性和灵敏度。SiO ₂通过化学气相沉积（CVD）原位沉积。SiO ₂膜使装饰有Pt的WO ₃传感器的工作温度低至150°C，并且灵敏度极高，即对150 ppm H ₂的响应为100,000 。相反，没有SiO ₂的传感器膜对150 ppm的响应仅为400。优异的性能可归因于氧气在SiO ₂膜中的低扩散速率，这导致在WO ₃表面上的氧气吸收很少。另外，SiO ₂膜也对氢具有高选择性。这项工作奠定了工程超灵敏和高选择性气体传感器的基础。除了特定的WO ₃材料以外，这项工作还可能有助于提高基于其他材料的氢传感器的性能。