Mechanisms behind sulfur promoted oxidation of methane
(2013) In Physical Chemistry Chemical Physics 15(22). p.8648-8661- Abstract
- The promoting effect of SO2 on the activity for methane oxidation over platinum supported on silica, alumina and ceria has been studied using a flow-reactor, in situ infrared spectroscopy and in situ high-energy X-ray diffraction experiments under transient reaction conditions. The catalytic activity is clearly dependent on the support material and its interaction with the noble metal both in the absence and presence of sulfur. On platinum, the competitive reactant adsorption favors oxygen dissociation such that oxygen self-poisoning is observed for Pt/silica and Pt/alumina. Contrarily for Pt/ceria, no oxygen self-poisoning is observed, which seems to be due to additional reaction channels via sites on the platinum-ceria boundary and/or... (More)
- The promoting effect of SO2 on the activity for methane oxidation over platinum supported on silica, alumina and ceria has been studied using a flow-reactor, in situ infrared spectroscopy and in situ high-energy X-ray diffraction experiments under transient reaction conditions. The catalytic activity is clearly dependent on the support material and its interaction with the noble metal both in the absence and presence of sulfur. On platinum, the competitive reactant adsorption favors oxygen dissociation such that oxygen self-poisoning is observed for Pt/silica and Pt/alumina. Contrarily for Pt/ceria, no oxygen self-poisoning is observed, which seems to be due to additional reaction channels via sites on the platinum-ceria boundary and/or ceria surface considerably far from the Pt crystallites. Addition of sulfur dioxide generally leads to the formation of ad-SOx species on the supports with a concomitant removal and/or blockage/rearrangement of surface hydroxyl groups. Thereby, the methane oxidation is inhibited for Pt/silica, enhanced for Pt/alumina and temporarily enhanced followed by inhibition after long-term exposure to sulfur for Pt/ceria. The observations can be explained by competitive oxidation of SO2 and CH4 on Pt/silica, formation of new active sites at the noble metal-support interface promoting dissociative adsorption of methane on Pt/alumina, and in the case of Pt/ceria, formation of promoting interfacial surface sulfates followed by formation of deactivating bulk-like sulfate species. Furthermore, it can be excluded that reduction of detrimental high oxygen coverage and/or oxide formation on the platinum particles through SO2 oxidation is the main cause for the promotional effects observed. (Less)
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https://lup.lub.lu.se/record/3932345
- author
- Bounechada, Djamela ; Fouladvand, Sheedeh ; Kylhammar, Lisa ; Pingel, Torben ; Olsson, Eva ; Skoglundh, Magnus ; Gustafson, Johan LU ; Di Michiel, Marco ; Newton, Mark A. and Carlsson, Per-Anders
- organization
- publishing date
- 2013
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Chemistry Chemical Physics
- volume
- 15
- issue
- 22
- pages
- 8648 - 8661
- publisher
- Royal Society of Chemistry
- external identifiers
-
- wos:000319006100021
- pmid:23439969
- scopus:85014058096
- ISSN
- 1463-9084
- DOI
- 10.1039/c3cp44289f
- language
- English
- LU publication?
- yes
- id
- e15e4961-46ba-4c44-947a-9a8d03c419f1 (old id 3932345)
- date added to LUP
- 2016-04-01 13:27:28
- date last changed
- 2022-01-27 19:19:41
@article{e15e4961-46ba-4c44-947a-9a8d03c419f1,
abstract = {{The promoting effect of SO2 on the activity for methane oxidation over platinum supported on silica, alumina and ceria has been studied using a flow-reactor, in situ infrared spectroscopy and in situ high-energy X-ray diffraction experiments under transient reaction conditions. The catalytic activity is clearly dependent on the support material and its interaction with the noble metal both in the absence and presence of sulfur. On platinum, the competitive reactant adsorption favors oxygen dissociation such that oxygen self-poisoning is observed for Pt/silica and Pt/alumina. Contrarily for Pt/ceria, no oxygen self-poisoning is observed, which seems to be due to additional reaction channels via sites on the platinum-ceria boundary and/or ceria surface considerably far from the Pt crystallites. Addition of sulfur dioxide generally leads to the formation of ad-SOx species on the supports with a concomitant removal and/or blockage/rearrangement of surface hydroxyl groups. Thereby, the methane oxidation is inhibited for Pt/silica, enhanced for Pt/alumina and temporarily enhanced followed by inhibition after long-term exposure to sulfur for Pt/ceria. The observations can be explained by competitive oxidation of SO2 and CH4 on Pt/silica, formation of new active sites at the noble metal-support interface promoting dissociative adsorption of methane on Pt/alumina, and in the case of Pt/ceria, formation of promoting interfacial surface sulfates followed by formation of deactivating bulk-like sulfate species. Furthermore, it can be excluded that reduction of detrimental high oxygen coverage and/or oxide formation on the platinum particles through SO2 oxidation is the main cause for the promotional effects observed.}},
author = {{Bounechada, Djamela and Fouladvand, Sheedeh and Kylhammar, Lisa and Pingel, Torben and Olsson, Eva and Skoglundh, Magnus and Gustafson, Johan and Di Michiel, Marco and Newton, Mark A. and Carlsson, Per-Anders}},
issn = {{1463-9084}},
language = {{eng}},
number = {{22}},
pages = {{8648--8661}},
publisher = {{Royal Society of Chemistry}},
series = {{Physical Chemistry Chemical Physics}},
title = {{Mechanisms behind sulfur promoted oxidation of methane}},
url = {{http://dx.doi.org/10.1039/c3cp44289f}},
doi = {{10.1039/c3cp44289f}},
volume = {{15}},
year = {{2013}},
}