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Hydrogen permeation...
Hydrogen permeation through surface modified Pd and PdAg membranes
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Amandusson, H. (author)
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- Ekedahl, Lars-Gunnar (author)
- Linköpings universitet,Tekniska högskolan,Institutionen för fysik, kemi och biologi
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- Dannetun, Helen (author)
- Linköpings universitet,Tekniska högskolan,Tillämpad Fysik
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(creator_code:org_t)
- 2001
- 2001
- English.
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In: Journal of Membrane Science. - 0376-7388 .- 1873-3123. ; 193:1, s. 35-47
- Related links:
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https://urn.kb.se/re...
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Abstract
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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.
Keyword
- Hydrogen
- Oxygen
- Palladium
- Permeation
- Silver
- TECHNOLOGY
- TEKNIKVETENSKAP
Publication and Content Type
- ref (subject category)
- art (subject category)
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