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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...

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Autores principales: 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
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2012
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).
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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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