NOx storage–reduction characteristics of Ba-based lean NOx trap catalysts subjected to simulated road aging

Ji, Yaying; Fisk, Courtney; Easterling, Vencon G.; Graham, Uschi M.; Poole, A.G.; Crocker, Mark; Choi, Jae‐Soon; Partridge, William P.; Wilson, Karen

doi:10.1016/j.cattod.2009.12.009

Cited by 33 publications

(34 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Vijay et al found that Co exhibits an ability similar to that of Pt to oxidize NO during the lean phase [7,8], while it is limited by its poor activity for catalyst regeneration during the rich phase. Addition of ceria to Pt/Ba/Al catalysts is reported to improve NO x storage capacity at low temperatures (<300 • C), while catalyst regeneration behavior is also improved as a consequence of the better dispersion of Pt on CeO 2 compared to BaO [9]. Manganese is also found to be an effective additive for Ba-based LNT catalysts.…”

Section: Introductionmentioning

confidence: 92%

NO storage and reduction properties of model manganese-based lean NO trap catalysts

Zhang

Chen

Wang

et al. 2015

Applied Catalysis B: Environmental

Self Cite

View full text Add to dashboard Cite

a b s t r a c tIn order to study the role of manganese in LNT catalysis, model Pd/Mn/Ba/Al, Pd/Mn/Al and Pd/Ba/Al catalysts were prepared and characterized. Both Mn-containing catalysts exhibited higher activity for NO oxidation to NO 2 than the Pd/Ba/Al reference catalyst, although NO x -TPD experiments showed that adsorbed NO x species were weakly bound on Pd/Mn/Al. Consequently, the presence of Ba was essential for high storage capacity. Compared to the Pd/Ba/Al reference, Pd/Mn/Ba/Al showed significantly improved NO x conversion under lean-rich cycling conditions as a consequence of its increased activity for NO oxidation and hence, superior NO x storage efficiency. In addition, the presence of Mn greatly lessened the inhibiting effects of H 2 O and CO 2 on cycle-averaged NO x conversion, this being due to the facile decomposition of manganese carbonate at low temperatures as evidenced by DRIFTS. Significantly, the Pd/Mn/Ba/Al catalyst displayed comparable activity to a traditional LNT catalyst of the Pt/Ba/Al type, showing the promising prospect of such new type of LNT catalysts.

show abstract

Section: Introductionmentioning

confidence: 92%

NO storage and reduction properties of model manganese-based lean NO trap catalysts

Zhang

Chen

Wang

et al. 2015

Applied Catalysis B: Environmental

Self Cite

View full text Add to dashboard Cite

show abstract

“…H2 pulsing was terminated after the TCD signal had reached a constant value, i.e., when the Pt sites were saturated with H2. Assuming a 1:1 ratio of atomic hydrogen to surface Pt, the metal dispersion was calculated based on the amount of H adsorbed [26].…”

Section: Catalyst Characterizationmentioning

confidence: 99%

Pt/Ce Pr1−O2 (x= 1 or 0.9) NO storage–reduction (NSR) catalysts

Rico-Pérez

Bueno‐López

Kim

et al. 2015

Applied Catalysis B: Environmental

Self Cite

View full text Add to dashboard Cite

Model Pt/Ce0.9Pr0.1O2 and Pt/CeO2 NOx storage-reduction catalysts were prepared via nitrate calcination, co-precipitation and carbon-templating routes.Raman spectroscopic data obtained on the catalysts indicated that the introduction of praseodymium into the ceria lattice increased the concentration of defect sites (vacancies), arising from the higher reducibility of the Pr 4+ cation compared to Ce 4+ . For the Pr-promoted samples, H2-TPR profiles contained high temperature bulk reduction peaks which were less pronounced compared with their ceria analogs, indicating that the presence of praseodymium enhances oxygen mobility due to the creation of lattice defects. Under lean-rich cycling conditions, the cycle-averaged NOx conversion of the Pt/Ce0.9Pr0.1O2samples was in each case substantially higher than that of the Pt/CeO2 analog, amounting to a difference of 10-15% in the absolute NOx conversion in some cases. According to DRIFTS data, a double role can be assigned to Pr doping; on the one hand, Pr accelerates the oxidation of adsorbed NOx species during the lean periods. On the other hand, Pr doping destabilizes the adsorbed NOx species during the rich periods, and the kinetics of nitrate decomposition are faster on Pt/Ce0.9Pr0.1O2, leading to improved catalyst regeneration. These results suggest that ceria-based mixed oxides incorporating Pr are promising materials for NOx storage-reduction catalysts intended for low temperature operation.

show abstract

“…However, this composition presents certain limitations, such as: i) reduction of the NOx storage capacity at temperature above 450°C, ii) low thermal stability, iii) catalyst poisoning by formation of barium carbonates and sulfates [10][11][12][13][14] and iv) unsatisfactory efficiency for certain applications, such as lean burn gasoline engines (GDI, gasoline direct injection), with exhaust temperatures as high as 400-500ºC [15]. Nowadays, an intense research is being carried out in order to propose alternatives to the use of noble metal-based catalysts for NSR able to work even at high temperatures (400-500ºC) [16].…”

Section: Introductionmentioning

confidence: 99%

BaTi1−xCuxO3 perovskites: The effect of copper content in the properties and in the NOx storage capacity

Albaladejo-Fuentes

López-Suárez

Sánchez-Adsuar

et al. 2014

Applied Catalysis A: General

View full text Add to dashboard Cite

Please cite this article as: V. Albaladejo-Fuentes, F.E. López-Suárez, M.S. Sánchez-Adsuar, M.J. Illán-Gómez, −x Cu x O 3 perovskites: the effect of copper content in the properties and in the NOx storage capacity., Applied Catalysis A, General (2014), http://dx.doi.org/10.1016/j.apcata. 2014.09.032 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. XRD and Raman spectroscopy results indicate that all the copper containing catalysts present a distortion of the original tetragonal structure due to the incorporation of copper into the lattice.The XPS and H 2 -TPR results reveal that the copper catalysts, except for BaTiCu0.5 catalyst, present two copper species (with different electronic interaction with the perovskite) and active surface oxygen species. Additionally, it seems that the fraction of copper with a strong electronic interaction with the perovskite or incorporated into the perovskite structure increases with the copper content.The active sites created on the BaTi 1-x Cu x O 3 perovskite surface bring to the catalysts activity for the NO to NO 2 oxidation and for the NOx adsorption. The NOx storage capacity increases with the copper content and reaches a limit for the BaTiCu2 catalyst (300 µmol/g, at 420ºC) which is within the range of the values reported for the noble metal-based catalysts.

show abstract

NOx storage–reduction characteristics of Ba-based lean NOx trap catalysts subjected to simulated road aging

Cited by 33 publications

References 56 publications

NO storage and reduction properties of model manganese-based lean NO trap catalysts

NO storage and reduction properties of model manganese-based lean NO trap catalysts

Pt/Ce Pr1−O2 (x= 1 or 0.9) NO storage–reduction (NSR) catalysts

BaTi1−xCuxO3 perovskites: The effect of copper content in the properties and in the NOx storage capacity

Contact Info

Product

Resources

About