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A transient response study of the selective catalytic oxidation of ammonia to nitrogen on Pt/CuO/Al2O3

Olofsson, Göran LU ; Hinz, Andreas and Andersson, Arne LU (2004) In Chemical Engineering Science 59(19). p.4113-4123
Abstract
The reaction mechanism for the selective catalytic oxidation of ammonia to give nitrogen on CuO/Al2O3, Pt/Al2O3 and Pt/CuO/Al2O3 was investigated using transient experiments. Temperature-programmed desorption and reaction of adsorbed ammonia indicated the formation of NHx species at the surface, and that this species is the precursor for the formation of nitrogen and nitrogen oxides. Pt/CuO/Al2O3 is the most active sample for nitrogen formation. In experiments pulsing alternately ammonia and oxygen it is observed that nitrogen is predominantly formed at the oxygen pulse on Pt/CuO/Al2O3 and at the ammonia pulse on Pt/Al2O3 and CuO/Al2O3. Results obtained in the alternate pulsing of ammonia and NO over preoxidised samples exclude NO from... (More)
The reaction mechanism for the selective catalytic oxidation of ammonia to give nitrogen on CuO/Al2O3, Pt/Al2O3 and Pt/CuO/Al2O3 was investigated using transient experiments. Temperature-programmed desorption and reaction of adsorbed ammonia indicated the formation of NHx species at the surface, and that this species is the precursor for the formation of nitrogen and nitrogen oxides. Pt/CuO/Al2O3 is the most active sample for nitrogen formation. In experiments pulsing alternately ammonia and oxygen it is observed that nitrogen is predominantly formed at the oxygen pulse on Pt/CuO/Al2O3 and at the ammonia pulse on Pt/Al2O3 and CuO/Al2O3. Results obtained in the alternate pulsing of ammonia and NO over preoxidised samples exclude NO from being a reaction intermediate for nitrogen formation. The performance of Pt/Al2O3 and CuO/Al2O3 in NH3-NO2 alternate pulsing reveals that nitrogen formation on these two samples occurs by formed NO2 reacts with an NHchi species. Over Pt/CuO/Al2O3, on the other hand, most nitrogen is formed by the direct oxidation and combination of two NHchi species using adsorbed oxygen. The data obtained suggests that the reaction takes place at the Pt/CuO phase boundary between NHx species being adsorbed on CuO and oxygen on Pt sites. (C) 2004 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Chemical Engineering Science
volume
59
issue
19
pages
4113 - 4123
publisher
Elsevier
external identifiers
  • wos:000224170500015
  • scopus:4544380963
ISSN
0009-2509
DOI
10.1016/j.ces.2004.03.047
language
English
LU publication?
yes
id
fdc877da-1e2e-40f3-9199-ed81194278cb (old id 138781)
date added to LUP
2007-06-25 14:20:04
date last changed
2017-03-26 04:22:32
@article{fdc877da-1e2e-40f3-9199-ed81194278cb,
  abstract     = {The reaction mechanism for the selective catalytic oxidation of ammonia to give nitrogen on CuO/Al2O3, Pt/Al2O3 and Pt/CuO/Al2O3 was investigated using transient experiments. Temperature-programmed desorption and reaction of adsorbed ammonia indicated the formation of NHx species at the surface, and that this species is the precursor for the formation of nitrogen and nitrogen oxides. Pt/CuO/Al2O3 is the most active sample for nitrogen formation. In experiments pulsing alternately ammonia and oxygen it is observed that nitrogen is predominantly formed at the oxygen pulse on Pt/CuO/Al2O3 and at the ammonia pulse on Pt/Al2O3 and CuO/Al2O3. Results obtained in the alternate pulsing of ammonia and NO over preoxidised samples exclude NO from being a reaction intermediate for nitrogen formation. The performance of Pt/Al2O3 and CuO/Al2O3 in NH3-NO2 alternate pulsing reveals that nitrogen formation on these two samples occurs by formed NO2 reacts with an NHchi species. Over Pt/CuO/Al2O3, on the other hand, most nitrogen is formed by the direct oxidation and combination of two NHchi species using adsorbed oxygen. The data obtained suggests that the reaction takes place at the Pt/CuO phase boundary between NHx species being adsorbed on CuO and oxygen on Pt sites. (C) 2004 Elsevier Ltd. All rights reserved.},
  author       = {Olofsson, Göran and Hinz, Andreas and Andersson, Arne},
  issn         = {0009-2509},
  language     = {eng},
  number       = {19},
  pages        = {4113--4123},
  publisher    = {Elsevier},
  series       = {Chemical Engineering Science},
  title        = {A transient response study of the selective catalytic oxidation of ammonia to nitrogen on Pt/CuO/Al2O3},
  url          = {http://dx.doi.org/10.1016/j.ces.2004.03.047},
  volume       = {59},
  year         = {2004},
}