The Role of Durability and Evaluation Conditions on the Performance of Pt/Rh and Pd/Rh Automotive Catalysts

Summers, James; Williamson, W. B.; Scaparo, John A.

doi:10.4271/900495

Cited by 18 publications

(2 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The first factor is purely economical, since palladium is presently the cheapest precious metal applicable in exhaust catalysis. Second, Pd-based techniques seem suitable in meeting the stringent future emission regulations, which will require better cold-start performance. − Several research groups have presented a new generation of palladium catalysts with and without the addition of Rh. ,− Fleet tests with new technology Pd−Rh catalysts have shown that Pd-based catalysts may be suitable for practical use in automotive exhaust catalysis…”

Section: Introductionmentioning

confidence: 99%

“…[14][15][16][17] Several research groups have presented a new generation of palladium catalysts with and without the addition of Rh. 10,[15][16][17][18][19][20] Fleet tests with new technology Pd-Rh catalysts have shown that Pd-based catalysts may be suitable for practical use in automotive exhaust catalysis. 21 To enhance the performance of Pd-based catalysts, different approaches have been tested, such as the use of Pd-Pt mixtures, 22 modification of the noble-metals impregnation method, 23 changes of the wash-coat crystalline structure, 24 and alteration of the wash-coat composition.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Behavior of Non-Promoted and Ceria-Promoted Pt/Rh and Pd/Rh Three-Way Catalysts under Steady State and Dynamic Operation of Hybrid Vehicles

Tagliaferri

Köppel

Baiker

1998

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

The suitability of newly developed non-promoted and ceria-promoted palladium−rhodium automotive catalysts for the exhaust gas control of a hybrid drive system has been tested by light-off experiments with steady and cycling feed stoichiometry, and pulsed-flow operation. The dynamic behavior of the honeycomb-type catalysts has been compared to the performance of standard honeycomb platinum−rhodium catalysts. Light-off tests carried out in the range 150−500 °C indicated significant differences in the conversion of NO x , CO, and hydrocarbons during warm-up, depending on the catalyst composition and whether λ-cycling was applied or not. Appropriate λ-cycling substantially improved the behavior of all catalysts in the lower light-off region. At higher temperatures cycling afforded lower conversions of all target components. Under pulsed-flow operation with an air pulse preceding the exhaust pulse (filling of the cylinder with air), asymmetric λ-cycling with longer rich half-cycles resulted in CO and HC conversions as well as N2 yields similar to or higher than those without an air pulse for the ceria-promoted catalysts. The catalytic tests suggest that ceria-promoted palladium is competitive to Pt−Rh−Ce in a hybrid vehicle application.

show abstract