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Chemistry of Supported Palladium Nanoparticles during Methane Oxidation

Nilsson, Johan; Carlsson, Per-Anders; Fouladvand, Sheedeh; Martin, Natalia M.; Gustafson, Johan LU ; Newton, Mark A.; Lundgren, Edvin LU ; Gronbeck, Henrik and Skoglundh, Magnus (2015) In ACS Catalysis 5(4). p.2481-2489
Abstract
Time-resolved in situ, energy-dispersive X-ray absorption spectroscopy and mass spectrometry are used to correlate changes in the chemical state of alumina- and ceria-supported palladium nanoparticles with changes in activity and selectivity for methane oxidation. Specifically, modulation excitation spectroscopy experiments are carried out by periodically cycling between net-reducing and net-oxidizing reaction conditions. The XANES and EXAFS data show that the palladium nanoparticles are readily bulk-oxidized when exposed to oxygen, forming a PdO-like phase, and reduced back to a reduced (metal) phase when oxygen is removed from the feed. The difference between the two support materials is most noticeable at the switches between... (More)
Time-resolved in situ, energy-dispersive X-ray absorption spectroscopy and mass spectrometry are used to correlate changes in the chemical state of alumina- and ceria-supported palladium nanoparticles with changes in activity and selectivity for methane oxidation. Specifically, modulation excitation spectroscopy experiments are carried out by periodically cycling between net-reducing and net-oxidizing reaction conditions. The XANES and EXAFS data show that the palladium nanoparticles are readily bulk-oxidized when exposed to oxygen, forming a PdO-like phase, and reduced back to a reduced (metal) phase when oxygen is removed from the feed. The difference between the two support materials is most noticeable at the switches between net-oxidizing and net-reducing reaction conditions. Here, a brief reduction in conversion is observed for the alumina-supported catalyst, but for the ceria-supported catalyst, this reduction in conversion is minor or not observed at all. This difference is attributed to differences in the oxidation kinetics and the oxygen storage capability of ceria. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
homogeneous catalysis, XAFS, in situ, methane, modulation excitation
in
ACS Catalysis
volume
5
issue
4
pages
2481 - 2489
publisher
The American Chemical Society
external identifiers
  • wos:000352464400053
  • scopus:84926433471
ISSN
2155-5435
DOI
10.1021/cs502036d
language
English
LU publication?
yes
id
fe72b028-a7fa-4987-ae3b-31fa4939d8eb (old id 5401383)
date added to LUP
2015-05-19 12:21:05
date last changed
2017-11-19 03:51:10
@article{fe72b028-a7fa-4987-ae3b-31fa4939d8eb,
  abstract     = {Time-resolved in situ, energy-dispersive X-ray absorption spectroscopy and mass spectrometry are used to correlate changes in the chemical state of alumina- and ceria-supported palladium nanoparticles with changes in activity and selectivity for methane oxidation. Specifically, modulation excitation spectroscopy experiments are carried out by periodically cycling between net-reducing and net-oxidizing reaction conditions. The XANES and EXAFS data show that the palladium nanoparticles are readily bulk-oxidized when exposed to oxygen, forming a PdO-like phase, and reduced back to a reduced (metal) phase when oxygen is removed from the feed. The difference between the two support materials is most noticeable at the switches between net-oxidizing and net-reducing reaction conditions. Here, a brief reduction in conversion is observed for the alumina-supported catalyst, but for the ceria-supported catalyst, this reduction in conversion is minor or not observed at all. This difference is attributed to differences in the oxidation kinetics and the oxygen storage capability of ceria.},
  author       = {Nilsson, Johan and Carlsson, Per-Anders and Fouladvand, Sheedeh and Martin, Natalia M. and Gustafson, Johan and Newton, Mark A. and Lundgren, Edvin and Gronbeck, Henrik and Skoglundh, Magnus},
  issn         = {2155-5435},
  keyword      = {homogeneous catalysis,XAFS,in situ,methane,modulation excitation},
  language     = {eng},
  number       = {4},
  pages        = {2481--2489},
  publisher    = {The American Chemical Society},
  series       = {ACS Catalysis},
  title        = {Chemistry of Supported Palladium Nanoparticles during Methane Oxidation},
  url          = {http://dx.doi.org/10.1021/cs502036d},
  volume       = {5},
  year         = {2015},
}