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Hydrogen permeation...
Hydrogen permeation through surface modified Pd and PdAg membranes
- Article/chapterEnglish2001
Publisher, publication year, extent ...
Numbers
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LIBRIS-ID:oai:DiVA.org:liu-47235
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https://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-47235URI
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https://doi.org/10.1016/S0376-7388(01)00414-8DOI
Supplementary language notes
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Language:English
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Summary in:English
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Subject category:ref swepub-contenttype
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Subject category:art swepub-publicationtype
Notes
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The hydrogen permeation through surface modified Pd and Pd70Ag30 membranes has been studied at temperatures between 100 and 350°C. Silver has been evaporated on Pd and Pd70Ag30 foils with a thickness of 25µm in order to study the role of the surface composition in comparison with the membrane bulk composition. The Pd70Ag30-based membranes display the largest permeation rates at temperatures below 200°C, while Pd membranes with 20Å silver evaporated on the upstream side show the largest permeation rates above 200°C. There are, consequently, different rate limiting processes above and below 200°C: at temperatures below 200°C, the bulk diffusion through the membrane is rate limiting, while at temperatures above 200°C, the influence of the surface composition starts to become significant. It has further been concluded that a sharp silver concentration gradient from the surface to the bulk is important for the hydrogen permeation rate at temperatures above 200°C. Adding oxygen to the hydrogen supply will almost totally inhibit the hydrogen permeation rate when a pure Pd membrane surface is facing the upstream side, while for silver-containing surfaces the presence of oxygen has almost no effect. On a clean Pd surface, oxygen effectively consumes adsorbed hydrogen in a water forming reaction. With Ag on the surface, no water formation is detected. Co-supplied CO inhibits the permeation of hydrogen in a similar manner on all studied membrane surfaces, independent of surface silver content. © 2001 Elsevier Science B.V. All rights reserved.
Subject headings and genre
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Hydrogen
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Oxygen
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Palladium
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Permeation
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Silver
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TECHNOLOGY
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TEKNIKVETENSKAP
Added entries (persons, corporate bodies, meetings, titles ...)
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Ekedahl, Lars-GunnarLinköpings universitet,Tekniska högskolan,Institutionen för fysik, kemi och biologi(Swepub:liu)larek85
(author)
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Dannetun, HelenLinköpings universitet,Tekniska högskolan,Tillämpad Fysik(Swepub:liu)helda31
(author)
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Linköpings universitetTekniska högskolan
(creator_code:org_t)
Related titles
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In:Journal of Membrane Science193:1, s. 35-470376-73881873-3123
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