Zhao Z, Sevryugina Y, Carpenter M A, Welch D, Xia H
College of NanoScale Science and Engineering and Department of Chemistry, University at Albany-SUNY, Albany, New York 12203, and MTI-Instruments, Albany, New York 12205, USA.
Anal Chem. 2004 Nov 1;76(21):6321-6. doi: 10.1021/ac0494883.
Optical reflectance measurements were performed to determine the hydrogen response characteristics of 20-nm-thick Pd-Au (Ag) films. The response characteristics displayed a strong dependence on alpha, mixed alpha/beta, and beta Pd-hydride phases formed in the films. The response time peaks in the alpha --> beta phase transition region (1625 s at 0.4% H(2) for Pd(0.94)Ag(0.06) and 405 s at 1% H(2) for Pd(0.94)Au(0.06)), consistent with critical slowing down phenomena. The alpha --> beta phase transition region was shifted and inhibited by changing the alloy element to Au and increasing its corresponding content to 40 atom %, respectively. Initial hydrogen uptake rate measurements determined that, due to the adsorption of ambient background gases, the rate-limiting step for alpha or beta phase PdH formation is dissociative chemisorption of hydrogen for each palladium alloy film. By tuning the alloy content and composition of the palladium films, the surface properties of the film become more receptive toward the rapid detection of hydrogen and a novel hydrogen-sensing material using Pd alloyed with 40 atom % Au is presented.
进行了光反射测量，以确定20纳米厚的钯-金（银）薄膜的氢响应特性。响应特性强烈依赖于薄膜中形成的α、混合α/β和β钯氢化物相。响应时间在α→β相变区域出现峰值（对于Pd(0.94)Ag(0.06)，在0.4% H₂时为1625秒；对于Pd(0.94)Au(0.06)，在1% H₂时为405秒），这与临界减慢现象一致。通过分别将合金元素换成金并将其相应含量增加到40原子%，α→β相变区域发生了偏移并受到抑制。初始氢吸收速率测量确定，由于环境背景气体的吸附，对于每种钯合金薄膜，α相或β相PdH形成的限速步骤是氢的解离化学吸附。通过调整钯薄膜的合金含量和组成，薄膜的表面性质对氢的快速检测变得更具接受性，并提出了一种使用40原子%金合金化的钯的新型氢传感材料。
