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<div class="csl-entry">Rameshan, C., Stadlmayr, W., Penner, S., Lorenz, H., Mayr, L., Haevecker, M., Blume, R., Rocha, T., Teschner, D., Knop-Gericke, A., Schlögl, R., Zemlyanov, D., Memmel, N., & Klötzer, B. (2012). In-situ XPS study of methanol reforming on PdGa near-surface intermetallic phases. <i>Journal of Catalysis</i>, <i>290</i>, 126–137. https://doi.org/10.1016/j.jcat.2012.03.009</div>
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dc.identifier.issn
0021-9517
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dc.identifier.uri
http://hdl.handle.net/20.500.12708/165021
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dc.description.abstract
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 CO2 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 PdxGa/Ga2O3 systems, which exhibit high CO2 selectivity in a broad temperature range. In contrast, corresponding experiments starting on the purely bimetallic model surface in oxidative methanol reforming yielded high CO2 selectivity already at low temperatures (∼460 K), which is due to efficient O2 activation on PdGa. In situ detected partial and reversible oxidative Ga segregation on intermetallic PdGa is associated with total oxidation of intermediate C1 oxygenates to CO2.
en
dc.language.iso
en
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dc.publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
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dc.relation.ispartof
Journal of Catalysis
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dc.subject
Catalysis
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dc.subject
Physical and Theoretical Chemistry
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dc.subject
Methanol dehydrogenation
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dc.subject
Methanol steam reforming
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dc.subject
Water activation
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dc.subject
PdGa near-surface intermetallic phase
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dc.subject
Oxidative steam reforming
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dc.subject
Ambient-pressure XPS
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dc.subject
In situ spectroscopy
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dc.title
In-situ XPS study of methanol reforming on PdGa near-surface intermetallic phases