Noble metal segregation and cluster size of Pt/Rh/CeO2/γ-Al2O3 automotive three-way catalysts studied with low-energy ion scattering

Autor: Jma Jan Harmsen, Arnoud Denier van der Gon, Jhbj Jozef Hoebink, JC Jaap Schouten, HH Hidde Brongersma, Wpa Wim Jansen
Přispěvatelé: Chemical Reactor Engineering, Applied Physics and Science Education
Jazyk: angličtina
Rok vydání: 2001
Předmět:
Zdroj: Journal of Catalysis, 204(2), 420-427. Academic Press Inc.
ISSN: 0021-9517
Popis: A method for determining the average cluster size of supported catalysts using low-energy ion scattering (LEIS) data is presented. The method is particularly suitable for determining the average cluster size of atomically dispersed metals and can be used for clusters as large as 10 nm. For Pt/γ-Al 2 O 3 quantitative agreement is shown between the average cluster size as determined with LEIS and that determined with transmission electron microscopy (TEM). In the case of three-way catalysts, classic methods for determining the cluster size, such as TEM or CO chemisorption, often fail or produce ambiguous results because of the presence of ceria. Therefore, LEIS has been applied to determine the average noble metal cluster size of a commercial three-way catalyst. Moreover, it is shown by LEIS that the three-way catalyst contains mixed Pt/Rh clusters, which are strongly enriched in surface Pt after reduction.
Databáze: OpenAIRE