Sulfur Poisoning Effects on Modern Lean NOx Trap Catalysts Components
Journal article, 2019

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 H-2 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.

platinum

magnesium

sulfur poisoning

palladium

lean NOx traps

ceria

Author

Jesus De Abreu Goes

Volvo Cars

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Chemical Engineering Design

Annika Kristoffersson

Volvo Cars

Louise Olsson

Chalmers, Chemistry and Chemical Engineering, Chemical Technology

Catalysts

2073-4344 (ISSN)

Vol. 9 6 492

Subject Categories

Materials Chemistry

Other Chemical Engineering

Other Chemistry Topics

DOI

10.3390/catal9060492

More information

Latest update

9/11/2019