Effect of hydrothermal aging on oxygen storage/release and activity in a commercial automotive catalyst

Schmieg, Steven J.; Belton, David N.

doi:10.1016/0926-3373(95)00011-9

Cited by 78 publications

(43 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The effects of hydrothermal aging on the oxygen storage/release and the activity of commercial automotive exhaust catalysts have been extensively investigated. [5] More recently, Winkler et al [6] reported the effects of aging processes and related phenomena on the catalytic behavior of threeway catalysts in a compressed natural gas/gasoline powered passenger car. These authors suggested that the formation of an outer metallic Pd layer over the catalytically PdO core could be responsible for the loss of activity in the methane oxidation.…”

Section: Introductionmentioning

confidence: 98%

XPS investigation of surface changes during thermal aging of Natural Gas Vehicle catalysts: Influence of Rh addition to Pd

Renème

Dhainaut

Trentesaux

et al. 2010

Surface & Interface Analysis

View full text Add to dashboard Cite

This study investigates thermal aging induced effects on the surface properties of model and commercial automotive catalysts for Natural Gas Vehicles, by means of X-ray photoelectron spectroscopy and infrared spectroscopy of chemisorbed CO as a probe molecule for noble metals. Post-combustion catalysts for this application are essentially composed of palladium containing low amounts of rhodium and additives to improve the oxygen storage properties. The aging procedure involved exposing the catalysts to an oxidizing atmosphere containing air and 10 vol.% H 2 O at 980• C for 4 h in order to simulate surface changes which may occur under usual three-way operating conditions. It was found that sintering processes led to a significant loss of Pd concentration on model and commercial catalysts. Regarding Rh, diffusion processes into alumina also take place, which are partially inhibited on model catalysts when Rh interacts with Pd. Greater stabilization of Rh species is suggested on commercial catalysts in the presence of oxygen storage materials.

show abstract

Section: Introductionmentioning

confidence: 98%

XPS investigation of surface changes during thermal aging of Natural Gas Vehicle catalysts: Influence of Rh addition to Pd

Renème

Dhainaut

Trentesaux

et al. 2010

Surface & Interface Analysis

View full text Add to dashboard Cite

show abstract

“…CeO 2 increases CO and hydrocarbon conversion during rich periods, and NO conversion during lean periods. Pure ceria systems lack thermal resistance and low -temperature activity [43] , but contacting CeO 2 with noble metals (such as Rh) can help the transfer of oxygen from the bulk to the surface [44] . With higher OSC of the catalyst, higher conversion efficiency and resistance to thermal aging are generally observed [45] .…”

Section: General Pointsmentioning

confidence: 99%

NO Heterogeneous Catalysis Viewed from the Angle of Nanoparticles

Thibault‐Starzyk

Daturi

Bazin

et al. 2007

Nanoparticles and Catalysis

View full text Add to dashboard Cite

“…These observations can be explained as being due to desorption of O 2 from the ceria containing materials (and the concomitant formation of Ce 3+ ) [16][17][18][19][20][21][22][23]. Initially this O 2 (rather than leaving the system) reacted with the PM and formed CO 2 .…”

Section: Formation Of Ce 3+ -Co Species From Reaction Between Cexzr1-mentioning

confidence: 99%

“…The rationale behind the use of these materials in this reaction is related to the oxygen storage capacity of the catalysts. CeO 2 can desorb and re-adsorb O 2 through formation and consumption of a Ce 2 O 3 oxide [16][17][18][19][20]. The oxygen atoms involved in this process are active for promotion of various combustion and reforming reactions [21][22][23][24][25] and for this reason (as well as their ability to dampen excursions to overly fuel rich or fuel lean exhaust conditions) Ce (x) Zr (1-x) O 2 catalysts are used as supports in many catalytic formulations.…”

Section: Introductionmentioning

confidence: 99%

Attempts at an in situ Raman study of ceria/zirconia catalysts in PM combustion

Sullivan

Dulgheru

Atribak

et al. 2011

Applied Catalysis B: Environmental

View full text Add to dashboard Cite

Publisher's statementThis is the author's version of a work that was accepted for publication in Applied Catalysis B: Environmental. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Applied Catalysis B: Environmental, 108-109 (1) Ce (x) Zr (1-x) O 2 catalysts with various Ce / Zr contents were studied using Raman spectroscopy under different gaseous atmospheres, at different temperatures and in the presence of a model soot.Catalysts with high concentrations of Zr fluoresced at elevated temperatures making analysis of their spectra impossible. This effect became even more pronounced at higher temperatures. CeO 2 and solid solutions with relatively low concentrations of Zr showed a red shift and a decrease in intensity of the characteristic F 2g peak at high temperatures under different atmospheres. The magnitude of the latter effect was higher under reducing atmospheres. These changes are reversible upon cooling, showing that they relate to a lattice expansion effect rather than any major chemical change to the material. In the presence of the model soot the Raman spectra of all materials was much decreased due to the absorption of the incident and scattered radiation by the soot particles. The presence of soot does not change the relative intensities or positions of the peaks in the spectra of the solid solutions. Evidence is shown for the production of a Ce 3+ -CO species following interaction between the soot and the surface at high temperature in an inert atmosphere.

show abstract

Effect of hydrothermal aging on oxygen storage/release and activity in a commercial automotive catalyst

Cited by 78 publications

References 16 publications

XPS investigation of surface changes during thermal aging of Natural Gas Vehicle catalysts: Influence of Rh addition to Pd

XPS investigation of surface changes during thermal aging of Natural Gas Vehicle catalysts: Influence of Rh addition to Pd

NO Heterogeneous Catalysis Viewed from the Angle of Nanoparticles

Attempts at an in situ Raman study of ceria/zirconia catalysts in PM combustion

Contact Info

Product

Resources

About