Sulfur Poisoning Effects on Modern Lean NOx Trap Catalysts Components
1
Volvo Cars, SE-405 31 Gothenburg, Sweden
2
Competence Centre for Catalysis, Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
*
Author to whom correspondence should be addressed.
Catalysts 2019, 9(6), 492; https://doi.org/10.3390/catal9060492
Received: 29 April 2019 / Revised: 20 May 2019 / Accepted: 24 May 2019 / Published: 28 May 2019
(This article belongs to the Special Issue Aftertreatment DeNOx Systems for Future Light Duty Lean-Burned Emission Regulations)
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.
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Keywords:
lean NOx traps; sulfur poisoning; platinum; palladium; magnesium; ceria
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MDPI and ACS Style
De Abreu Goes, J.E.; Kristoffersson, A.; Olsson, L. Sulfur Poisoning Effects on Modern Lean NOx Trap Catalysts Components. Catalysts 2019, 9, 492. https://doi.org/10.3390/catal9060492
AMA Style
De Abreu Goes JE, Kristoffersson A, Olsson L. Sulfur Poisoning Effects on Modern Lean NOx Trap Catalysts Components. Catalysts. 2019; 9(6):492. https://doi.org/10.3390/catal9060492
Chicago/Turabian StyleDe Abreu Goes, Jesus E.; Kristoffersson, Annika; Olsson, Louise. 2019. "Sulfur Poisoning Effects on Modern Lean NOx Trap Catalysts Components" Catalysts 9, no. 6: 492. https://doi.org/10.3390/catal9060492
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