Pd films on soft substrates: a visual, high-contrast and low-cost optical hydrogen sensor

For the rapid development of the hydrogen economy, a reliable and low-cost hydrogen sensor appears to be extremely important. Here, we first show that a palladium film deposited on polydimethylsiloxane (PDMS) can obtain an exceedingly high-reflectance contrast of 25.78 over the entire visible band upon exposure to 4 vol% hydrogen gas (H-2) mixed with nitrogen gas. This high-reflectance contrast results from the surface deformation induced by the volume inflation after exposure to H-2, leading to the transition of the near-specular surface to a diffusing surface. In addition, a change in brightness is readable by naked eye upon exposure to H-2 with various concentrations from 0.6 to 1 vol% under the illumination of a fluorescent tube. Furthermore, this sensor possesses an excellent recyclability and quick response time of a few seconds. Compared with Pd nanostructure-based hydrogen sensors, this visual, high-contrast and low-cost sensor is of great potential for practical hydrogen sensing.

对于氢经济的快速发展，可靠且低成本的氢传感器显得极其重要。在此，我们首先表明，沉积在聚二甲基硅氧烷（PDMS）上的钯膜在暴露于与氮气混合的4%（体积分数）氢气（H₂）时，在整个可见光波段可获得25.78的极高反射率对比度。这种高反射率对比度是由暴露于H₂后体积膨胀引起的表面变形导致的，这使得近镜面表面转变为漫射表面。此外，在荧光灯管照明下，当暴露于浓度从0.6%到1%（体积分数）的各种H₂时，肉眼可观察到亮度变化。而且，该传感器具有出色的可重复使用性和几秒的快速响应时间。与基于钯纳米结构的氢传感器相比，这种可视化、高对比度且低成本的传感器在实际氢传感方面具有巨大潜力。