Hydrogen permeation and stability in ultra-thin Pd-Ru supported membranes
Hydrogen permeation and stability in ultra-thin Pd-Ru supported membranes
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超薄 Pd-Ru 支撑膜的氢渗透和稳定性
DOI：
10.1016/j.ijhydene.2019.03.212
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发表时间：
2020-03-04
影响因子：
7.2
通讯作者：
Caravella, Alessio
中科院分区：
文献类型：
--
作者：
Liu, Jinxia;Bellini, Stefano;Caravella, Alessio
在本文中，我们报告的性能支持钯钌膜可能应用于氢气纯化和/或生产。为此，我们采用组合电镀技术制备了三种超薄α-氧化铝支撑膜：Pd-Ag膜（3 μ m厚，约1.5 μ m）;和两个Pd-Ru（约1.8 μ m厚）。前者被设定为比较的基准。膜的特点是使用不同的方法：渗透试验，热处理和SEM分析。用氮气进行的初步泄漏测试表明，两种Pd-Ru膜，即PdRu#1和PdRu#2，显示出非理想的（非无限的）选择性，前者相对较低（在400 ℃下约为830），而后者足够高（在400 ℃下为2645）。这表明在PdRu#2膜中存在相关缺陷，与对Pd-Ag和PdRu#1膜观察到的不同。渗透测试表明，氢渗透通量在高达约550 ℃时是稳定的，在较高温度（600 ℃）下具有明显的不寻常行为，其中我们观察到氢通量随着氮通量的增加而略微降低。此外，通过SEM图像分析，在使用后的所有膜的金属层中观察到奇特的气泡状结构。这是通过考虑Pd合金晶粒表面能的影响来解释的，Pd合金晶粒表面能倾向于通过在晶格中产生球状气泡来最小化晶粒界面的暴露表面积，类似于水中肥皂泡发生的情况。上述在600 ℃下氢通量的降低被解释为是由气泡形成引起的，气泡形成将合金更深地推入支撑孔中。(C)2019年氢能出版有限责任公司。由爱思唯尔有限公司出版。保留所有权利。
In this paper, we report the performance of supported Pd-Ru membranes for possible applications to hydrogen purification and/or production. For this purpose, we fabricated three ultra-thin a-alumina-supported membranes by combined plating techniques: a Pd- Ag membrane (3 mu m-thick ca.) and two Pd-Ru (1.8 mu m-thick ca.). The former is set as a benchmark for comparison. The membranes were characterised using different methodologies: permeation tests, thermal treatment and SEM analysis. Preliminary leakage tests performed with nitrogen has revealed that the two Pd-Ru membranes, namely PdRu#1 and PdRu#2, show a non-ideal (non-infinite) selectivity, which is relatively low for the former (around 830 at 400 degrees C) and sufficiently high for the latter (2645 at 400 degrees C). This indicates a relevant presence of defects in the PdRu#2 membrane, differently from what observed for the Pd-Ag and PdRu#1 ones. The permeation tests show that the hydrogen permeating flux is stable up to around 550 degrees C, with an apparently unusual behaviour at higher temperatures (600 degrees C), where we observe a slightly decrease of hydrogen flux with an increase of the nitrogen one. Moreover, a peculiar bubble-shaped structure is observed in the metal layer of all membranes after usage by means of SEM image analysis. This is explained by considering the effect of the Pd-alloy grain surface energy, which tends to minimise the exposed surface area of the grain interface by creating sphere-like bubble in the lattice, similar to what occurs for soap bubbles in water. The above-mentioned decrease in hydrogen flux at 600 degrees C is explained to be caused by the bubble formation, which pushes the alloy deeper in the support pores. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.