Impact of Pt-Rh and Pd-Rh Interactions on Performance of Bimetal Catalysts

Nunan, John; Williamson, W. B.; Robota, Heinz J.; Henk, M. G.

doi:10.4271/950258

Cited by 33 publications

(4 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However it is important that those noble metals occupy a particular position in the monolith to operate properly, which requires the development of advanced impregnation techniques in order to avoid alloying effect during three-way operating conditions . By way of illustration, it is usual that Pd forms alloyed particles with Rh inducing a loss of the intrinsic properties of Pd and Rh in the reaction involved in three-way conditions . Typically, noble metals are well-dispersed after impregnation of highly porous alumina wash-coat (20−40 μm) on ceramic honeycomb structures or monoliths.…”

Section: Three-way Catalysts and Related Systemsmentioning

confidence: 99%

Catalytic NO_x Abatement Systems for Mobile Sources: From Three-Way to Lean Burn after-Treatment Technologies

2011

View full text Add to dashboard Cite

Section: Three-way Catalysts and Related Systemsmentioning

confidence: 99%

Catalytic NO_x Abatement Systems for Mobile Sources: From Three-Way to Lean Burn after-Treatment Technologies

2011

View full text Add to dashboard Cite

“…Their association in a single catalyst can nevertheless positively or negatively alter their behavior as well as their interaction with somy wash-coat components. In the case of bimetallic Pt-Rh catalysts, for example, alloying does not modify the Rh function but hinders the saturated HC function of Pt (26). For Pd-Rh catalysts, alloying has more negative effects, suppressing the Rh function for CO and espe-cially for NO (25).…”

Section: Fig 12mentioning

confidence: 99%

Catalytic automotive exhaust gas depollution: Present status and new trends

Prigent

1996

Bulletin des Soc Chimique

View full text Add to dashboard Cite

Journ6e de Contact en Catalyse de la Communauth Franpaise de Belgique : "Catalyse par les metaux" le 7 dbcembre 1995, Bruxelles ABSTRACTA review is made of the various types of exhaust gas aftertreatment systems presently used on most vehicles to reduce pdlutant emissions. The systems are differentiated by their mode of action, according to the engine type to be depolluted (2-strokes, 4-strokes, diesel or spark-ignition), and by their type of make-up. The major developmentsforeseen in the future, in view of compliance with the new legislations, are described. Means enabling some prototype vehicles with internal combustion engines to emit pollutant quantities really close to zero, such as electric cars, are described.

show abstract

“…al. [64] reported that Pt is more effective than Pd for saturated HC oxidation, however Pd shows light-off at lower temperatures than Pt.…”

Section: I T T Y Ymentioning

confidence: 99%

“…1000 K, where PdO decomposes and leads to catalyst deactivation [61,34] . It shows light-off at lower temperatures than Pt, [ 64 ] and great resistance in thermal ageing [65] , but it is sensitive to poisoning by sulfur and lead compounds [69] .…”

Section: A T a L Y T I C A L L Y A C T I V E P H A S E Smentioning

confidence: 99%

Development and application of a computer aided engineering methodology supporting the design optimization of automotive exhaust treatment systems

Konstantas¹

View full text Add to dashboard Cite

O p t i m i z a t i o n o f A u t o m o t i v e E x h a u s t T r e a t m e n t S y s t e m sTHESIS submitted in partial fulfillment of the requirements for the degree of D o c t o r o f P h i l o s o p h y i n M e c h a n i c a l E n g i n e e r i n g of the D e p a r t m e n t o f M e c h a n i c a l a n d I n d u s t r i a l E n g i n e e r i n g -3 - Since the core of almost every automotive exhaust aftertreatment system is some kind of catalytic converter, intensive research activity is devoted to the various scientific and technical aspects of catalytic technology. These aspects vary from practical research on new materials and novel techniques to improve catalyst microstructure, to theoretical contributions of detailed descriptions of chemical phenomena inside the converters and proposals of mechanistic reaction schemes.Nevertheless, the extremely high efficiencies that are expected from any modern catalyst cannot be attained without simultaneously optimizing aftertreatment device performance, engine design and the control system that drives the whole system. Thus, from a mechanical engineer's point of view, the exhaust treatment complexity is expressed as a strong interaction between these three fields: powertrain operation, engine management characteristics and exhaust treatment device operation.In general, the composition of exhaust gas depends on the engine type, the operating point of the engine, the ambient temperature, the transmission system and miscellaneous characteristics of each system. Thus, the engine management holds a key role in the behavior of the catalytic converter, since it affects both its input as well as the temperature range under which it operates. Moreover, exhaust line design, involving exhaust manifold heat capacity, insulated pipes and positioning of the devices, is strongly connected with the catalytic converter operation. Furthermore, catalysts with the same chemical composition may behave quite differently, depending on the actual procedures that were employed during catalyst preparation.The complexity of the automotive exhaust treatment systems quickly became apparent in the industry. Mathematical modeling tools are continuously developed, in order to complement the experimental efforts and provide guidance for areas that needed improvement. In the last 30 years, many models have appeared in the literature [2] . Their approaches and their scope were diverse, but in general they were rather focused on the individual devices than on the whole aftertreatment system. -6 -Specifically for the catalytic converter modeling: most kinetic studies so far resulted in models that are valid for the specific combination of engine and catalyst status at that moment (usually fresh catalysts). Although valuable for a specific engineering problem, such modeling results could only partially be extended in different systems, and only with great caution. Indeed, successful extension of the results of a specific case to another one is rare in the literature [1] . As a characteristic example...

show abstract

Impact of Pt-Rh and Pd-Rh Interactions on Performance of Bimetal Catalysts

Cited by 33 publications

References 11 publications

Catalytic NO_x Abatement Systems for Mobile Sources: From Three-Way to Lean Burn after-Treatment Technologies

Catalytic NO_x Abatement Systems for Mobile Sources: From Three-Way to Lean Burn after-Treatment Technologies

Catalytic automotive exhaust gas depollution: Present status and new trends

Development and application of a computer aided engineering methodology supporting the design optimization of automotive exhaust treatment systems

Contact Info

Product

Resources

About

Impact of Pt-Rh and Pd-Rh Interactions on Performance of Bimetal Catalysts

Cited by 33 publications

References 11 publications

Catalytic NOx Abatement Systems for Mobile Sources: From Three-Way to Lean Burn after-Treatment Technologies

Catalytic NOx Abatement Systems for Mobile Sources: From Three-Way to Lean Burn after-Treatment Technologies

Catalytic automotive exhaust gas depollution: Present status and new trends

Development and application of a computer aided engineering methodology supporting the design optimization of automotive exhaust treatment systems

Contact Info

Product

Resources

About

Catalytic NO_x Abatement Systems for Mobile Sources: From Three-Way to Lean Burn after-Treatment Technologies

Catalytic NO_x Abatement Systems for Mobile Sources: From Three-Way to Lean Burn after-Treatment Technologies