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CO Oxidation and Site Speciation for Alloyed Palladium-Platinum Model Catalysts Studied by in Situ FTIR Spectroscopy

Martin, Natalia M. LU ; Skoglundh, Magnus; Smedler, Gudmund; Raj, Agnes; Thompsett, David; Velin, Peter; Martinez-Casado, Francisco J.; Matej, Zdenek LU ; Balmes, Olivier LU and Carlsson, Per Anders LU (2017) In Journal of Physical Chemistry C 121(47). p.26321-26329
Abstract

In situ Fourier transform infrared spectroscopy was used to study transient CO oxidation over a series of bimetallic Pd-Pt catalysts with different Pd:Pt molar ratios. The catalysts were found to contain both alloyed PdPt nanoparticles (particle sizes 25-35 nm) and monometallic Pd nanoparticles (sizes below 10 nm). For oxygen-free conditions, CO reduces the surface while simultaneously function as a chemical probe molecule whereby the CO adsorption sites can be characterized. Under these conditions, it is shown that adsorbed carbonyl species form both on the Pd and Pt. On platinum, CO adsorbs predominantly linearly on top, whereas on palladium it adsorbes in bridged configurations. This behavior is used for site speciation of the... (More)

In situ Fourier transform infrared spectroscopy was used to study transient CO oxidation over a series of bimetallic Pd-Pt catalysts with different Pd:Pt molar ratios. The catalysts were found to contain both alloyed PdPt nanoparticles (particle sizes 25-35 nm) and monometallic Pd nanoparticles (sizes below 10 nm). For oxygen-free conditions, CO reduces the surface while simultaneously function as a chemical probe molecule whereby the CO adsorption sites can be characterized. Under these conditions, it is shown that adsorbed carbonyl species form both on the Pd and Pt. On platinum, CO adsorbs predominantly linearly on top, whereas on palladium it adsorbes in bridged configurations. This behavior is used for site speciation of the catalysts. The spectra from the bimetallic Pd-Pt catalysts are more complicated than a direct superposition of the spectra for the monometallic catalysts as a consequence of alloy formation and enrichment of Pd at the surface of the reduced catalysts. The temperature-programmed CO oxidation results show that the addition of Pd to the Pt catalyst supported on alumina shifts the CO-poisoned state to lower temperatures, therefore increasing the temperature range for the CO oxidation at low temperatures.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Physical Chemistry C
volume
121
issue
47
pages
9 pages
publisher
The American Chemical Society
external identifiers
  • scopus:85037061487
  • wos:000417228500021
ISSN
1932-7447
DOI
10.1021/acs.jpcc.7b07611
language
English
LU publication?
yes
id
4e8b81b6-6052-4fd8-aff2-abe652c7fbf9
date added to LUP
2017-12-21 14:26:01
date last changed
2018-01-16 13:28:31
@article{4e8b81b6-6052-4fd8-aff2-abe652c7fbf9,
  abstract     = {<p>In situ Fourier transform infrared spectroscopy was used to study transient CO oxidation over a series of bimetallic Pd-Pt catalysts with different Pd:Pt molar ratios. The catalysts were found to contain both alloyed PdPt nanoparticles (particle sizes 25-35 nm) and monometallic Pd nanoparticles (sizes below 10 nm). For oxygen-free conditions, CO reduces the surface while simultaneously function as a chemical probe molecule whereby the CO adsorption sites can be characterized. Under these conditions, it is shown that adsorbed carbonyl species form both on the Pd and Pt. On platinum, CO adsorbs predominantly linearly on top, whereas on palladium it adsorbes in bridged configurations. This behavior is used for site speciation of the catalysts. The spectra from the bimetallic Pd-Pt catalysts are more complicated than a direct superposition of the spectra for the monometallic catalysts as a consequence of alloy formation and enrichment of Pd at the surface of the reduced catalysts. The temperature-programmed CO oxidation results show that the addition of Pd to the Pt catalyst supported on alumina shifts the CO-poisoned state to lower temperatures, therefore increasing the temperature range for the CO oxidation at low temperatures.</p>},
  author       = {Martin, Natalia M. and Skoglundh, Magnus and Smedler, Gudmund and Raj, Agnes and Thompsett, David and Velin, Peter and Martinez-Casado, Francisco J. and Matej, Zdenek and Balmes, Olivier and Carlsson, Per Anders},
  issn         = {1932-7447},
  language     = {eng},
  month        = {11},
  number       = {47},
  pages        = {26321--26329},
  publisher    = {The American Chemical Society},
  series       = {Journal of Physical Chemistry C},
  title        = {CO Oxidation and Site Speciation for Alloyed Palladium-Platinum Model Catalysts Studied by in Situ FTIR Spectroscopy},
  url          = {http://dx.doi.org/10.1021/acs.jpcc.7b07611},
  volume       = {121},
  year         = {2017},
}