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In situ XPS study of methanol reforming on PdGa near-surface intermetallic phases
In situ X-ray photoelectron spectroscopy and low-energy ion scattering were used to study the preparation, (thermo)chemical and catalytic properties of 1:1 PdGa intermetallic near-surface phases. Deposition of several multilayers of Ga metal and subsequent annealing to 503–523 K led to the formation...
Autores principales: | , , , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Elsevier
2012
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3405296/ https://www.ncbi.nlm.nih.gov/pubmed/22875996 http://dx.doi.org/10.1016/j.jcat.2012.03.009 |
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author | Rameshan, Christoph Stadlmayr, Werner Penner, Simon Lorenz, Harald Mayr, Lukas Hävecker, Michael Blume, Raoul Rocha, Tulio Teschner, Detre Knop-Gericke, Axel Schlögl, Robert Zemlyanov, Dmitry Memmel, Norbert Klötzer, Bernhard |
author_facet | Rameshan, Christoph Stadlmayr, Werner Penner, Simon Lorenz, Harald Mayr, Lukas Hävecker, Michael Blume, Raoul Rocha, Tulio Teschner, Detre Knop-Gericke, Axel Schlögl, Robert Zemlyanov, Dmitry Memmel, Norbert Klötzer, Bernhard |
author_sort | Rameshan, Christoph |
collection | PubMed |
description | In situ X-ray photoelectron spectroscopy and low-energy ion scattering were used to study the preparation, (thermo)chemical and catalytic properties of 1:1 PdGa intermetallic near-surface phases. Deposition of several multilayers of Ga metal and subsequent annealing to 503–523 K led to the formation of a multi-layered 1:1 PdGa near-surface state without desorption of excess Ga to the gas phase. In general, the composition of the PdGa model system is much more variable than that of its PdZn counterpart, which results in gradual changes of the near-surface composition with increasing annealing or reaction temperature. In contrast to near-surface PdZn, in methanol steam reforming, no temperature region with pronounced CO(2) selectivity was observed, which is due to the inability of purely intermetallic PdGa to efficiently activate water. This allows to pinpoint the water-activating role of the intermetallic/support interface and/or of the oxide support in the related supported Pd(x)Ga/Ga(2)O(3) systems, which exhibit high CO(2) selectivity in a broad temperature range. In contrast, corresponding experiments starting on the purely bimetallic model surface in oxidative methanol reforming yielded high CO(2) selectivity already at low temperatures (∼460 K), which is due to efficient O(2) activation on PdGa. In situ detected partial and reversible oxidative Ga segregation on intermetallic PdGa is associated with total oxidation of intermediate C(1) oxygenates to CO(2). |
format | Online Article Text |
id | pubmed-3405296 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2012 |
publisher | Elsevier |
record_format | MEDLINE/PubMed |
spelling | pubmed-34052962012-08-06 In situ XPS study of methanol reforming on PdGa near-surface intermetallic phases Rameshan, Christoph Stadlmayr, Werner Penner, Simon Lorenz, Harald Mayr, Lukas Hävecker, Michael Blume, Raoul Rocha, Tulio Teschner, Detre Knop-Gericke, Axel Schlögl, Robert Zemlyanov, Dmitry Memmel, Norbert Klötzer, Bernhard J Catal Article In situ X-ray photoelectron spectroscopy and low-energy ion scattering were used to study the preparation, (thermo)chemical and catalytic properties of 1:1 PdGa intermetallic near-surface phases. Deposition of several multilayers of Ga metal and subsequent annealing to 503–523 K led to the formation of a multi-layered 1:1 PdGa near-surface state without desorption of excess Ga to the gas phase. In general, the composition of the PdGa model system is much more variable than that of its PdZn counterpart, which results in gradual changes of the near-surface composition with increasing annealing or reaction temperature. In contrast to near-surface PdZn, in methanol steam reforming, no temperature region with pronounced CO(2) selectivity was observed, which is due to the inability of purely intermetallic PdGa to efficiently activate water. This allows to pinpoint the water-activating role of the intermetallic/support interface and/or of the oxide support in the related supported Pd(x)Ga/Ga(2)O(3) systems, which exhibit high CO(2) selectivity in a broad temperature range. In contrast, corresponding experiments starting on the purely bimetallic model surface in oxidative methanol reforming yielded high CO(2) selectivity already at low temperatures (∼460 K), which is due to efficient O(2) activation on PdGa. In situ detected partial and reversible oxidative Ga segregation on intermetallic PdGa is associated with total oxidation of intermediate C(1) oxygenates to CO(2). Elsevier 2012-06 /pmc/articles/PMC3405296/ /pubmed/22875996 http://dx.doi.org/10.1016/j.jcat.2012.03.009 Text en © 2012 Elsevier Inc. https://creativecommons.org/licenses/by-nc-nd/3.0/ Open Access under CC BY-NC-ND 3.0 (https://creativecommons.org/licenses/by-nc-nd/3.0/) license |
spellingShingle | Article Rameshan, Christoph Stadlmayr, Werner Penner, Simon Lorenz, Harald Mayr, Lukas Hävecker, Michael Blume, Raoul Rocha, Tulio Teschner, Detre Knop-Gericke, Axel Schlögl, Robert Zemlyanov, Dmitry Memmel, Norbert Klötzer, Bernhard In situ XPS study of methanol reforming on PdGa near-surface intermetallic phases |
title | In situ XPS study of methanol reforming on PdGa near-surface intermetallic phases |
title_full | In situ XPS study of methanol reforming on PdGa near-surface intermetallic phases |
title_fullStr | In situ XPS study of methanol reforming on PdGa near-surface intermetallic phases |
title_full_unstemmed | In situ XPS study of methanol reforming on PdGa near-surface intermetallic phases |
title_short | In situ XPS study of methanol reforming on PdGa near-surface intermetallic phases |
title_sort | in situ xps study of methanol reforming on pdga near-surface intermetallic phases |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3405296/ https://www.ncbi.nlm.nih.gov/pubmed/22875996 http://dx.doi.org/10.1016/j.jcat.2012.03.009 |
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