Prediction of Hydrogen Flux Through Sulfur-Tolerant Binary Alloy Membranes

Kamakoti, Preeti; Morreale, Bryan D.; Ciocco, Michael V.; Howard, Bret H.; Killmeyer, R.P.; Cugini, A.V.; Sholl, David S.

doi:10.1126/science.1107041

Cited by 259 publications

(217 citation statements)

References 22 publications

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“…Our predicted permeability is more than an order magnitude larger than the permeabilities predicted and measured by Kamakoti et al [8], however, it is consistent with the Ma et al [9] H permeability of the Pd 0.47 Cu 0.53 B2 phase being 1.1 times that of Pd at 623 K. The predicted permeabilities calculations and related parameters are summarized in Table 3. …”

Section: De-fg26-05nt42453 United Technologies Research Centersupporting

confidence: 50%

Advanced Water-Gas Shift Membrane Reactor

Emerson¹,

Vanderspurt²,

Opalka³

et al. 2009

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The overall objectives for this project were: (1) to identify a suitable PdCu trimetallic alloy membrane with high stability and commercially relevant hydrogen permeation in the presence of trace amounts of carbon monoxide and sulfur; and (2) to identify and synthesize a water gas shift catalyst with a high operating life that is sulfur and chlorine tolerant at low concentrations of these impurities. This work successfully achieved the first project objective to identify a suitable PdCu tri-metallic alloy membrane composition, Pd 0.47 Cu 0.52 G5 0.01 , that was selected based on atomistic and thermodynamic modeling alone. The second objective was partially successful in that catalysts were identified and evaluated that can withstand sulfur in high concentrations and at high pressures, but a long operating life was not achieved at the end of the project. From the limited durability testing it appears that the best catalyst, Pt-Re/Ce 0.333 Zr 0.333 E4 0.333 O 2 , is unable to maintain a long operating life at space velocities of 200,000 h -1 . The reasons for the low durability do not appear to be related to the high concentrations of H 2 S, but rather due to the high operating pressure and the influence the pressure has on the WGS reaction at this space velocity.ii

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Section: De-fg26-05nt42453 United Technologies Research Centersupporting

confidence: 50%

Advanced Water-Gas Shift Membrane Reactor

Emerson¹,

Vanderspurt²,

Opalka³

et al. 2009

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“…[6][7][8][9] Because of its importance in several areas, surface diffusion has been the focus of many experimental and theoretical studies involving a variety of adsorbates and surfaces, and there are many comprehensive reviews of the subject. [10][11][12][13][14][15][16][17] In spite of this widespread interest, however, very few general principles for diffusion on surfaces have been identified.…”

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confidence: 99%

A Simple Rule of Thumb for Diffusion on Transition‐Metal Surfaces

2006

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Diffusion of adsorbed species on solid surfaces involves the thermally activated lateral motion of these species. Among others, diffusion on surfaces plays an important role in many industrial heterogeneously catalyzed reactions and in crystal growth and aggregation processes. [1] Furthermore, an improved understanding of surface diffusion phenomena is relevant for characterizing the local deformation of metal surfaces, [2] and for analyzing the dynamics of metal corrosion.[3] Similarly, surface diffusion plays a key role in the transport of species in catalytic reactions, [4,5] as well as in the growth of surface nanostructures and the accumulation of subsurface/bulk species below metal surfaces. [6][7][8][9] Because of its importance in several areas, surface diffusion has been the focus of many experimental and theoretical studies involving a variety of adsorbates and surfaces, and there are many comprehensive reviews of the subject. [10][11][12][13][14][15][16][17] In spite of this widespread interest, however, very few general principles for diffusion on surfaces have been identified. Herein, we propose and provide quantitative evidence for two important principles: 1) that there is a simple correlation between the diffusion barrier and the binding energy of various species on transition-metal surfaces, and 2) that there is practically no compensation effect between the preexponential factor and the activation energy barrier for diffusion of adsorbed species on transition-metal surfaces.Recent theoretical studies of surface-catalyzed bondbreaking reactions of diatomic molecules have elucidated some simple linear correlations between the transition-state (TS) energy and the final-state (FS) energy of the respective elementary steps. These Brønsted-Evans-Polanyi-type correlations span a wide range of energies and include several metal and alloy surfaces, which suggests the existence of a universality class for these simple catalytic reactions. [18][19][20] This universality reflects an inherent similarity between the TS and the FS structures. Such correlations are of great practical relevance to experimentalists, as they provide convenient

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“…The small He leak growth rates seen in N_02 and N_03 could be due to the fact that the solubility of hydrogen in Pd/Cu alloys decreased with Cu content [38]. Since the He leak growth was faster in a H 2 atmosphere than in a He atmosphere [36,39], less H 2 dissolved in the lattice could have decreased the leak growth.…”

Section: Pd/cu Membrane Fabrication and Characterizationmentioning

confidence: 99%

Sulfur Tolerant Pd/Cu and Pd/Au Alloy Membranes for H2 Separation with High Pressure CO2 for Sequestration

Hua¹,

Pomerantz²,

Chen³

2008

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The effect of H 2 S poisoning on Pd, Pd/Cu, and Pd/Au alloy composite membranes prepared by the electroless deposition method on porous Inconel supports was investigated to provide a fundamental understanding of the durability and preparation of sulfur tolerant membranes. X-ray photoelectron spectroscopy (XPS) studies showed that the exposure of pure Pd to 50 ppm H 2 S/H 2 mixtures caused bulk sulfide formation at lower temperatures and surface sulfide formation at higher temperatures. Lower temperatures, longer exposure times, and higher H 2 S concentrations resulted in a higher degree of sulfidation. In a Pd membrane, the bulk sulfide formation caused a drastic irrecoverable H 2 permeance decline and an irreparable loss in selectivity.Pd/Cu and Pd/Au alloy membranes exhibited permeance declines due to surface sulfide formation upon exposure to 50 ppm H 2 S/H 2 gas mixtures. However in contrast to the pure Pd membrane, the permeances of the Pd/Cu and Pd/Au alloy membranes were mostly recovered in pure H 2 and the selectivity of the Pd alloy layers remained essentially intact throughout the characterization in H 2 , He and H 2 S/H 2 mixtures which lasted several thousand hours. The amount of irreversible sulfur poisoning decreased with increasing temperature due to the exothermicity of H 2 S adsorption. Longer exposure times increased the amount of irreversible poisoning of the Pd/Cu membrane but not the Pd/Au membrane.Pd/Au coupon studies of the galvanic displacement method showed that higher Au 3+ concentrations, lower pH values, higher bath temperatures and stirring the bath at a rate of 200 rpm yielded faster displacement rates, more uniform depositions, and a higher Au content within the layers. While 400ºC was found to be sufficient to form a Pd/Au alloy

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Prediction of Hydrogen Flux Through Sulfur-Tolerant Binary Alloy Membranes

Cited by 259 publications

References 22 publications

Advanced Water-Gas Shift Membrane Reactor

Advanced Water-Gas Shift Membrane Reactor

A Simple Rule of Thumb for Diffusion on Transition‐Metal Surfaces

Sulfur Tolerant Pd/Cu and Pd/Au Alloy Membranes for H2 Separation with High Pressure CO2 for Sequestration

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