Combined XPS and SIMS measurements, partly supplemented by XRD investigations, were utilized to detect precious metal/support interactions on catalysts containing various precious metals. The Klemm-Bronger reaction between Pt and alpha-Al2O3 on methane/ammonia catalysts was used as a standard reference. Evidence was found for different stages of Pt/Al interactions and changing electronic properties of Pt on the surfaces of these Pt/ alpha-Al2O3 catalysts by means of XPS and SIMS, and in the bulk material by XRD. The SIMS investigations on Pt and Rh on gamma-Al2O3 showed that, even at temperatures around 500 C, Rh/Al interactions can appear to a small extent in the topmost atomic layers, whereas the Pt/ gamma-Al2O3 specimens did not show any measurable effects. After on-road operation, enhanced SIMS cluster-ion signals as well as anomalous XPS signal contributions were measured on the surfaces of used three-way automotive emission control catalysts. These signals did not appear for the fresh catalysts. By analogy with the related results reported on the methane/ammonia catalysts, the ion signals were used as qualitative surface probes indicating the presence of precious metal/support interactions, especially between Rh and Al.
Investigations on precious metal/alumina interactions on three-way automative emission control catalysts, BMA catalysts and model samples
Chemical Engineering and Technology ; 17 , 3 ; 161-168
1994
8 Seiten
Aufsatz (Zeitschrift)
Englisch
Erforschung , Edelmetall , Ammoniak , Standard , Elektronik , Schüttgut , Temperatur , Emissionsüberwachung , Ion , Probe , Al2O3 , Modell , Aluminium , Analysenmesstechnik , Beobachtung , Beugung (Strahl) , Direktbeobachtung , Fahrzeug , Fluoreszenzspektralanalyse , Katalysator , Kraftfahrzeug , Leichtmetalle , Materialeigenschaft , Messen , Messtechnik , Metalle , NE-Metall , Nichtmetallverbindung , Oxid , Reaktionsbeschleuniger , Reinmetall , RFA-Analyse , Sauerstoffverbindung , Spektrometrie
Tema Archiv | 1985
|Advanced three-way catalysts - optimisation by targeted zoning of precious metal
Kraftfahrwesen | 2005
|Catalytic Control of Exhaust Emissions by Metal supported Precious Metal Catalysts
Kraftfahrwesen | 1977
|SLUB | 2013
|