Hydrogen permeation of thin, free-standing Pd/Ag23% membranes before and after heat treatment in air

Mejdell, A.L.; Klette, H.; Ramachandran, A.; Borg, A.; Bredesen, Rune

doi:10.1016/j.memsci.2007.09.024

Cited by 91 publications

(51 citation statements)

References 28 publications

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“…Additionally, the two types of membranes responded differently to oxidative pre-conditioning. Previous research in sputtered Pd-Ag alloys has demonstrated that the history of a given membrane has a significant effect upon its performance, with pretreatment under air at 573 K (as was done in this work) producing improved hydrogen permeability [16]. Control experiments, in which membranes were heated under nitrogen rather than air, did duplicate these results for the sputtered membranes.…”

Section: Hydrogen Permeability At 623 K For Various Alloys Of Palladisupporting

confidence: 64%

Effects of fabrication technique upon material properties and permeation characteristics of palladium-gold alloy membranes for hydrogen separations

2010

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This work highlights new research into the fundamental properties of palladium-gold alloy membranes. Two types of self-supported palladium-gold foils were studied; membranes produced by magnetron sputtering and membranes produced by cold-working. The cold-worked membranes had thicknesses of 25 microns and gold contents from 0-40 wt% Au, while the sputtered films ranged from 10-31 microns in thickness and 5-10 wt% Au. These films were characterized by single-gas permeation testing in the temperature range of 473-773K and at pressures of up to 772 kPa. Membranes were studied before and after testing by XRD, XPS, XRF, and SEM/EDS.Hydrogen permeability in the 0-20 wt Au% range was found to be a function of synthesis technique as much as alloy content, with no single alloy having superior permeability at all temperatures. Sputtered materials had generally higher permeability than cold-worked materials of equivalent composition, although the thicker sputtered membrane had reduced hydrogen permeability compared to its thinner counterparts.

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Section: Hydrogen Permeability At 623 K For Various Alloys Of Palladisupporting

confidence: 64%

Effects of fabrication technique upon material properties and permeation characteristics of palladium-gold alloy membranes for hydrogen separations

2010

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“…The disk sample is set into a cell for the hydrogen permeation test apparatus and then evacuated. Subsequently, so-called air-treatment is performed 18) . First, the sample cell is heated up to 500 C. Then ambient pressure of air is introduced into the system and wait for 600 s. The sample cell is evacuated again and then high purity (99.99999%) hydrogen gas is introduced into the system.…”

Section: Hydrogen Permeation Testsmentioning

confidence: 99%

Anomalous Temperature Dependence of Hydrogen Permeability through Palladium–Silver Binary Alloy Membrane and Its Analysis Based on Hydrogen Chemical Potential

et al. 2016

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The hydrogen permeability of Pd-Ag alloy membranes has been investigated over a wide temperature range between 100 C and 500 C. The hydrogen permeation coef cient, Φ, for Pd-23mol%Ag decreases with decreasing temperature above 300 C, in good agreement with the previous literature. However, Φ starts to increases below 250 C, and a peak is observed at around 180 C. Considering the silver concentration and operating temperature, the α-α phase transition never occurs in this condition. In other words, the α-α phase transition is not the reason for the anomalous peak behavior of Pd-23mol%Ag alloy at low temperature. In addition, it is con rmed that the diffusion-limiting hydrogen permeation reaction takes place from room temperature up to 500 C. To understand the reason for the peak appearance, the hydrogen permeability has been analyzed in view of the new description of hydrogen permeation based on hydrogen chemical potential. As a result, it is found that the temperature dependence of the PCT factor, f PCT , is dominant for the peak appearance, meaning that the corresponding pressure-composition-isotherms (PCT curves) are essential for the understanding of hydrogen permeability of the alloy. Dependences of the pressure condition and silver concentration on the peak behavior have also been investigated. The peak temperature increases with increasing the hydrogen pressure at feed side. In addition, the peak appears at lower temperature and becomes remarkable with decreasing silver concentration of Pd-Ag alloy membrane. In other words, the composition of Pd-Ag alloy membranes must be designed based on the operating temperature or pressure condition. Thus, this study suggests new possibilities of alloy design for Pd-Ag alloy membranes.

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“…However the permeance of our membranes was two or three orders of magnitude higher than typical one of capillary transport. Based on these findings, it is concluded that the gas permeation in this membrane follows the Knudsen diffusion [1,3], although we could not rule out capillary transport mechanism completely.…”

Section: (C) It Was Clearly Confirmed That the Pd Nanoparticlesmentioning

confidence: 65%

“…In general, thinner and denser membranes show high performance for hydrogen permeation due to decreasing time through the membrane and increasing collision frequency between gas and wall of micro pore in membrane, respectively. Pd and its alloy membranes are commercially used because they have higher permeability of hydrogen than that of the other gases [2,3]. However, making thin membrane less than 2 m from Pd and its alloy by conventional methods is expensive and difficult [2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Hydrogen Permeable Membrane Using Nanoparticles Electrophoresis Technique

et al. 2009

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Hydrogen perm-selective membranes composed of Pd nanoparticles were investigated.The nanoparticles were prepared by ultrasonic reduction from Pd II ions, and then deposited on a substrate disc with electrophoresis technique. These electrophoretic membranes have shown high performance of perm-selectivity for H 2 with separation factor =3.85, under room temperature. KeywordThin membrane · Hydrogen perm-selectivity · Electrophoresis · Nanoparticels 3

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Hydrogen permeation of thin, free-standing Pd/Ag23% membranes before and after heat treatment in air

Cited by 91 publications

References 28 publications

Effects of fabrication technique upon material properties and permeation characteristics of palladium-gold alloy membranes for hydrogen separations

Effects of fabrication technique upon material properties and permeation characteristics of palladium-gold alloy membranes for hydrogen separations

Anomalous Temperature Dependence of Hydrogen Permeability through Palladium–Silver Binary Alloy Membrane and Its Analysis Based on Hydrogen Chemical Potential

Preparation of Hydrogen Permeable Membrane Using Nanoparticles Electrophoresis Technique

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