Effects of low Ag additions on the hydrogen permeability of Pd–Cu–Ag hydrogen separation membranes

Nayebossadri, Shahrouz; Speight, J.D.; Book, D. L.

doi:10.1016/j.memsci.2013.10.002

Cited by 71 publications

(50 citation statements)

References 46 publications

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“…The FCC lattice parameter of Membrane A was determined using XRD data analysis giving an average of 3.757 ± 0.003 Å comparable to published values of the same alloy composition which range from 3.75 to 3.763 Å [39][40][41][42][43]. Using Eq.…”

Section: Eqsupporting

confidence: 58%

Effects of thin film Pd deposition on the hydrogen permeability of Pd 60 Cu 40 wt% alloy membranes

Al-Mufachi

Nayebossadri

Speight

et al. 2015

Journal of Membrane Science

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Effects of thin film Pd deposition on the Hydrogen permeability of Pd 60 Cu 40 wt% alloy membranes, Journal of Membrane Science, http://dx. AbstractPd 60 Cu 40 wt% (Pd 47.3 Cu 52.7 at%) membranes were surface modified by depositing Pd thin films of three different thicknesses (~100, 800 and 1,400 nm) on to one side of a range of as-received Pd 60 Cu 40 wt% cold-rolled foils via magnetron sputtering. The hydrogen permeability of the membranes was then measured and compared to uncoated material. The Pd 60 Cu 40 wt% membrane coated with a 1,400 nm thick Pd thin film positioned on the feed side (445 kPa of hydrogen pressure) during hydrogen permeability measurements and cycled between 50 and 450 °C achieved the highest hydrogen permeability of 1.09  10 -8 mol m -1 s -1 Pa -0.5 at 450 °C in the third cycle. This is a 58% increase on the value measured for the as-received Pd 60 Cu 40 wt% under the same conditions. This improvement can be attributed to a Pd-rich Pd-Cu face centred cubic (FCC) phase forming through interdiffusion between the Pd thin film and bulk Pd-Cu membrane as a result of the test conditions used during hydrogen permeability measurements. This introduces a larger concentration gradient across the membrane due to the relatively high hydrogen solubility of the Pd-rich Pd-Cu FCC phase resulting in the observed increase in permeability.The Pd 60 Cu 40 wt% membranes coated with a ~1,400 nm and ~800 nm thick Pd thin film retained an almost pure Pd surface throughout cycling between 50 and 450 °C with a feed and permeate hydrogen pressure of 445 and 100 kPa, respectively. This is possibly due to the clamping effect of the Pd-Cu membrane substrate applied on the Pd thin film which would prevent embrittlement caused by cycling across the critical temperature of 295 °C. 2

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Section: Eqsupporting

confidence: 58%

Effects of thin film Pd deposition on the hydrogen permeability of Pd 60 Cu 40 wt% alloy membranes

Al-Mufachi

Nayebossadri

Speight

et al. 2015

Journal of Membrane Science

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“…where T is the absolute temperature at which equilibrium is obtained, if not particularly defined, T is chosen as 600 K as avoid to the two-phase regions in the Pd-alloys with absorbed hydrogen [39]. Clearly, if ).…”

Section: Langmuir-mclean Equation For Equilibrium Segregationmentioning

confidence: 99%

Modelling of surface segregation for palladium alloys in vacuum and gas environments

Zhao

Sloof

Böttger

2018

International Journal of Hydrogen Energy

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Surface segregation of a series of forty Palladium-based binary alloys has been investigated using a thermodynamic model based on an atom exchange approach. Their surface segregation behaviour, both in vacuum and in gas environments, were comprehensively estimated. The calculated results are in good agreement with the available experimental and computational data reported in literatures. Effects of mixing enthalpy, temperature, crystal orientation on the surface, elastic strain energy, adsorption and absorption of gases like H 2 , O 2 , CO have been discussed in detail. These results can be considered as basic guidelines to design novel Pd alloys for hydrogen separation membranes, sensors or catalysts. The model itself also offers a convenient and accurate routine to predict the surface segregation of other than Pd-based binary alloys in different gas atmospheres.

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“…It appears that the potential of binary Pd-based membranes has been exhausted in the literature, and several groups have recently started working on ternary compounds as the next generation membrane material [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. This has many possible benefits: the surface can be engineered to enhance the tolerance to impurity gases [ 13 ], the permeability can be optimized beyond what is possible with binary alloys [ 14 ], and the mechanical strength can be increased (e.g., if the self-diffusion is hindered or the morphology is changed) [ 2 ].…”

Section: Introductionmentioning

confidence: 99%

Grain Boundary Segregation in Pd-Cu-Ag Alloys for High Permeability Hydrogen Separation Membranes

Løvvik

Zhao

et al. 2018

Membranes

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Dense metal membranes that are based on palladium (Pd) are promising for hydrogen separation and production due to their high selectivity and permeability. Optimization of alloy composition has normally focused on bulk properties, but there is growing evidence that grain boundaries (GBs) play a crucial role in the overall performance of membranes. The present study provides parameters and analyses of GBs in the ternary Pd-Ag-Cu system, based on first-principles electronic structure calculations. The segregation tendency of Cu, Ag, and vacancies towards 12 different coherent ∑ GBs in Pd was quantified using three different procedures for relaxation of supercell lattice constants, representing the outer bounds of infinitely elastic and stiff lattice around the GBs. This demonstrated a clear linear correlation between the excess volume and the GB energy when volume relaxation was allowed for. The point defects were attracted by most of the GBs that were investigated. Realistic atomic-scale models of binary Pd-Cu and ternary Pd-Cu-Ag alloys were created for the ∑5(210) boundary, in which the strong GB segregation tendency was affirmed. This is a starting point for more targeted engineering of alloys and grain structure in dense metal membranes and related systems.

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Effects of low Ag additions on the hydrogen permeability of Pd–Cu–Ag hydrogen separation membranes

Cited by 71 publications

References 46 publications

Effects of thin film Pd deposition on the hydrogen permeability of Pd 60 Cu 40 wt% alloy membranes

Effects of thin film Pd deposition on the hydrogen permeability of Pd 60 Cu 40 wt% alloy membranes

Modelling of surface segregation for palladium alloys in vacuum and gas environments

Grain Boundary Segregation in Pd-Cu-Ag Alloys for High Permeability Hydrogen Separation Membranes

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