Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
ACS Nano. 2011 Sep 27;5(9):7443-52. doi: 10.1021/nn2023717. Epub 2011 Aug 24.
The newly developed hydrogen sensor, based on a network of ultrasmall pure palladium nanowires sputter-deposited on a filtration membrane, takes advantage of single palladium nanowires' characteristics of high speed and sensitivity while eliminating their nanofabrication obstacles. However, this new type of sensor, like the single palladium nanowires, cannot distinguish hydrogen concentrations above 3%, thus limiting the potential applications of the sensor. This study reports hydrogen sensors based on a network of ultrasmall Cr-buffered Pd (Pd/Cr) nanowires on a filtration membrane. These sensors not only are able to outperform their pure Pd counterparts in speed and durability but also allow hydrogen detection at concentrations up to 100%. The new networks consist of a thin layer of palladium deposited on top of a Cr adhesion layer 1-3 nm thick. Although the Cr layer is insensitive to hydrogen, it enables the formation of a network of continuous Pd/Cr nanowires with thicknesses of the Pd layer as thin as 2 nm. The improved performance of the Pd/Cr sensors can be attributed to the increased surface area to volume ratio and to the confinement-induced suppression of the phase transition from Pd/H solid solution (α-phase) to Pd hydride (β-phase).
新开发的氢气传感器基于溅射沉积在过滤膜上的超细纯钯纳米线网络，利用了单钯纳米线高速和高灵敏度的特点，同时消除了它们的纳米制造障碍。然而，与单钯纳米线一样，这种新型传感器无法区分浓度高于 3%的氢气，从而限制了传感器的潜在应用。本研究报告了基于过滤膜上的 Cr 缓冲 Pd（Pd/Cr）纳米线网络的氢气传感器。这些传感器不仅在速度和耐久性方面优于纯 Pd 对应物，而且还能够检测高达 100%浓度的氢气。新网络由厚度为 1-3nm 的 Cr 附着层上沉积的一层薄钯组成。尽管 Cr 层对氢气不敏感，但它能够形成连续的 Pd/Cr 纳米线网络，其 Pd 层厚度薄至 2nm。Pd/Cr 传感器性能的提高可归因于表面积与体积比的增加以及受限诱导的 Pd/H 固溶体（α 相）向 Pd 氢化物（β 相）的相变抑制。
