Sulfur Poisoning Effects on Modern Lean NOx Trap Catalysts Components

In the present work, a series of different materials was investigated in order to enhance the understanding of the role of modern lean NOx trap (LNT) components on the sulfur poisoning and regeneration characteristics. Nine different types of model catalysts were prepared, which mainly consisted of...

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Bibliographic Details
Published in:Catalysts 2019-06, Vol.9 (6), p.492
Main Authors: De Abreu Goes, Jesus Emmanuel, Kristoffersson, Annika, Olsson, Louise
Format: Article
Language:English
Subjects:
Adsorption
Aluminum oxide
Barium
Bimetals
Catalysts
ceria
Cerium oxides
Chemical reactions
Decomposition
Emission standards
Emissions
Energy efficiency
Experiments
Formulations
Fourier transform spectrometers
High temperature
Infrared spectrometers
lean NOx traps
Low temperature
Magnesium
Metals
Noble metals
Palladium
Platinum
Poisoning
Regeneration
Spectrum analysis
Stability
Sulfur
sulfur poisoning
Sulfur removal
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Summary:In the present work, a series of different materials was investigated in order to enhance the understanding of the role of modern lean NOx trap (LNT) components on the sulfur poisoning and regeneration characteristics. Nine different types of model catalysts were prepared, which mainly consisted of three compounds: (i) Al2O3, (ii) Mg/Al2O3, and (iii) Mg/Ce/Al2O3 mixed with Pt, Pd, and Pt-Pd. A micro flow reactor and a diffuse reflectance infrared Fourier transform spectrometer (DRIFTS) were employed in order to investigate the evolution and stability of the species formed during SO2 poisoning. The results showed that the addition of palladium and magnesium into the LNT formulation can be beneficial for the catalyst desulfation due mainly to the ability to release the sulfur trapped at relatively low temperatures. This was especially evident for Pd/Mg/Al2O3 model catalyst, which demonstrated an efficient LNT desulfation with low H2 consumption. In contrast, the addition of ceria was found to increase the formation of bulk sulfate species during SO2 poisoning, which requires higher temperatures for the sulfur removal. The noble metal nature was also observed to play an important role on the SOx storage and release properties. Monometallic Pd-based catalysts exhibited the formation of surface palladium sulfate species during SO2 exposure, whereas Pt-Pd bimetallic formulations presented higher stability of the sulfur species formed compared to the corresponding Pt- and Pd-monometallic samples.
ISSN:2073-4344
2073-4344
DOI:10.3390/catal9060492