Walter E C, Favier F, Penner R M
Department of Chemistry, University of California, Irvine 92679-2025, USA.
Anal Chem. 2002 Apr 1;74(7):1546-53. doi: 10.1021/ac0110449.
Arrays of mesoscopic palladium wires prepared by electrodeposition form the basis for hydrogen sensors and hydrogen-actuated switches that exhibit a response time ranging from 20 ms to 5 s, depending on the hydrogen concentration. These devices were constructed by electrodepositing palladium mesowires on a highly oriented pyrolytic graphite surface and then transferring these mesowires to a cyanoacrylate film supported on a glass slide. The application of silver contacts to the ends of 10-100 mesowires, arrayed electrically in parallel, produced sensors and switches that exhibited a high conductivity state in the presence of hydrogen and a low conductivity state in the absence of hydrogen. After an initial exposure to hydrogen, 15-50 nanoscopic gaps are formed in each mesowire. These nanoscopic gaps or "break junctions" close in the presence of hydrogen gas and reopen in its absence as hydrogen is reversibly occluded by the palladium grains in each wire, and the palladium lattice expands and contracts by several percent. The change in resistance for sensors and switches was related to the hydrogen concentration over a range from 1 to 10%.
通过电沉积制备的介观钯丝阵列构成了氢传感器和氢驱动开关的基础，这些传感器和开关的响应时间根据氢浓度在20毫秒到5秒之间变化。这些器件是通过在高度取向的热解石墨表面上电沉积钯中丝，然后将这些中丝转移到支撑在载玻片上的氰基丙烯酸酯薄膜上构建而成的。在10 - 100根中丝的末端施加银触点，这些中丝以电并联方式排列，制成的传感器和开关在有氢存在时呈现高导电状态，在无氢时呈现低导电状态。在初次暴露于氢之后，每根中丝中会形成15 - 50个纳米级间隙。这些纳米级间隙或“断裂结”在有氢气存在时闭合，在无氢气时重新打开，因为氢气被每根丝中的钯晶粒可逆地吸收，并且钯晶格会膨胀和收缩百分之几。传感器和开关的电阻变化在1%到10%的范围内与氢浓度相关。
