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Tracking the shape-dependent sintering of platinum-rhodium model catalysts under operando conditions.

Hejral, Uta; Müller, Patrick; Balmes, Olivier LU ; Pontoni, Diego and Stierle, Andreas (2016) In Nature Communications 7.
Abstract
Nanoparticle sintering during catalytic reactions is a major cause for catalyst deactivation. Understanding its atomic-scale processes and finding strategies to reduce it is of paramount scientific and economic interest. Here, we report on the composition-dependent three-dimensional restructuring of epitaxial platinum-rhodium alloy nanoparticles on alumina during carbon monoxide oxidation at 550 K and near-atmospheric pressures employing in situ high-energy grazing incidence x-ray diffraction, online mass spectrometry and a combinatorial sample design. For platinum-rich particles our results disclose a dramatic reaction-induced height increase, accompanied by a corresponding reduction of the total particle surface coverage. We find this... (More)
Nanoparticle sintering during catalytic reactions is a major cause for catalyst deactivation. Understanding its atomic-scale processes and finding strategies to reduce it is of paramount scientific and economic interest. Here, we report on the composition-dependent three-dimensional restructuring of epitaxial platinum-rhodium alloy nanoparticles on alumina during carbon monoxide oxidation at 550 K and near-atmospheric pressures employing in situ high-energy grazing incidence x-ray diffraction, online mass spectrometry and a combinatorial sample design. For platinum-rich particles our results disclose a dramatic reaction-induced height increase, accompanied by a corresponding reduction of the total particle surface coverage. We find this restructuring to be progressively reduced for particles with increasing rhodium composition. We explain our observations by a carbon monoxide oxidation promoted non-classical Ostwald ripening process during which smaller particles are destabilized by the heat of reaction. Its driving force lies in the initial particle shape which features for platinum-rich particles a kinetically stabilized, low aspect ratio. (Less)
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type
Contribution to journal
publication status
published
subject
in
Nature Communications
volume
7
publisher
Nature Publishing Group
external identifiers
  • pmid:26957204
  • scopus:84960509989
  • wos:000371731000001
ISSN
2041-1723
DOI
10.1038/ncomms10964
language
English
LU publication?
yes
id
6f9cca82-88bc-4c01-a04c-080aaf59d002 (old id 8852966)
date added to LUP
2016-03-23 13:42:29
date last changed
2017-11-12 03:49:56
@article{6f9cca82-88bc-4c01-a04c-080aaf59d002,
  abstract     = {Nanoparticle sintering during catalytic reactions is a major cause for catalyst deactivation. Understanding its atomic-scale processes and finding strategies to reduce it is of paramount scientific and economic interest. Here, we report on the composition-dependent three-dimensional restructuring of epitaxial platinum-rhodium alloy nanoparticles on alumina during carbon monoxide oxidation at 550 K and near-atmospheric pressures employing in situ high-energy grazing incidence x-ray diffraction, online mass spectrometry and a combinatorial sample design. For platinum-rich particles our results disclose a dramatic reaction-induced height increase, accompanied by a corresponding reduction of the total particle surface coverage. We find this restructuring to be progressively reduced for particles with increasing rhodium composition. We explain our observations by a carbon monoxide oxidation promoted non-classical Ostwald ripening process during which smaller particles are destabilized by the heat of reaction. Its driving force lies in the initial particle shape which features for platinum-rich particles a kinetically stabilized, low aspect ratio.},
  articleno    = {10964},
  author       = {Hejral, Uta and Müller, Patrick and Balmes, Olivier and Pontoni, Diego and Stierle, Andreas},
  issn         = {2041-1723},
  language     = {eng},
  publisher    = {Nature Publishing Group},
  series       = {Nature Communications},
  title        = {Tracking the shape-dependent sintering of platinum-rhodium model catalysts under operando conditions.},
  url          = {http://dx.doi.org/10.1038/ncomms10964},
  volume       = {7},
  year         = {2016},
}