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Title: Characterization of model three-way catalysts. 3: Infrared study of the surface composition of platinum-rhodium ceria-alumina catalysts

Abstract

The surface composition of model and commercial bimetallic PtRh catalysts supported on ceria-alumina was tentatively determined by FTIR spectroscopy using the successive adsorption of NO at 473 K and CO at 298 K method which was previously applied to the case of PtRh/Al{sub 2}O{sub 3} catalysts. The study of monometallic model catalysts shows that the adsorption of NO at 473 K on rhodium gives an intense band at 1912 cm{sup {minus}1} which is not modified by the presence of ceria and therefore can be used to quantify the number of surface rhodium atoms. However, the chemisorption properties of platinum toward the subsequent adsorption of CO at 298 K are strongly modified and the quantification of the surface platinum atoms could not be directly measured. However, their number could be indirectly obtained by combining the NO adsorption for rhodium and hydrogen volumetric adsorption for the total number of surface metal atoms, assuming that NO adsorption does not induce an important segregation of rhodium for bimetallic particles. Thus, for the fresh bimetallic model catalyst, the same composition was obtained at the surface and in the bulk. After aging at 1273 K, no rhodium was detected at the surface. This absence of surfacemore » rhodium atoms was confirmed by the data obtained from the direct adsorption of CO on platinum at room temperature, which gave the same number of surface atoms as hydrogen chemisorption. Similar results have been obtained with two commercial three-way catalysts. In particular, after aging at 1273 K, rhodium was practically not detected on the surface.« less

Authors:
; ; ;  [1];  [2];  [3];  [4];  [5]
  1. CNRS/Univ. Claude Bernard Lyon 1, Villeurbanne (France). Lab. d`Application de la Chimie a l`Environnement
  2. Inst. de Recherches sur la Catalyse, Villeurbanne (France)
  3. Technocentre Renault, Guyancourt (France)
  4. Renault, Lardy (France). Direction de l`Ingenierie des Materiaux
  5. Renault, Rueil Malmaison (France). Direction de la Recherche
Publication Date:
OSTI Identifier:
687749
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis
Additional Journal Information:
Journal Volume: 186; Journal Issue: 2; Other Information: PBD: 10 Sep 1999
Country of Publication:
United States
Language:
English
Subject:
33 ADVANCED PROPULSION SYSTEMS; 54 ENVIRONMENTAL SCIENCES; CATALYTIC CONVERTERS; CATALYSTS; PLATINUM; RHODIUM; CERIUM OXIDES; ALUMINIUM OXIDES; SURFACE PROPERTIES; NITRIC OXIDE; CARBON MONOXIDE; ADSORPTION

Citation Formats

Rogemond, E., Frety, R., Perrichon, V., Primet, M., Essayem, N., Chevrier, M., Gauthier, C., and Mathis, F. Characterization of model three-way catalysts. 3: Infrared study of the surface composition of platinum-rhodium ceria-alumina catalysts. United States: N. p., 1999. Web. doi:10.1006/jcat.1999.2585.
Rogemond, E., Frety, R., Perrichon, V., Primet, M., Essayem, N., Chevrier, M., Gauthier, C., & Mathis, F. Characterization of model three-way catalysts. 3: Infrared study of the surface composition of platinum-rhodium ceria-alumina catalysts. United States. doi:10.1006/jcat.1999.2585.
Rogemond, E., Frety, R., Perrichon, V., Primet, M., Essayem, N., Chevrier, M., Gauthier, C., and Mathis, F. Fri . "Characterization of model three-way catalysts. 3: Infrared study of the surface composition of platinum-rhodium ceria-alumina catalysts". United States. doi:10.1006/jcat.1999.2585.
@article{osti_687749,
title = {Characterization of model three-way catalysts. 3: Infrared study of the surface composition of platinum-rhodium ceria-alumina catalysts},
author = {Rogemond, E. and Frety, R. and Perrichon, V. and Primet, M. and Essayem, N. and Chevrier, M. and Gauthier, C. and Mathis, F.},
abstractNote = {The surface composition of model and commercial bimetallic PtRh catalysts supported on ceria-alumina was tentatively determined by FTIR spectroscopy using the successive adsorption of NO at 473 K and CO at 298 K method which was previously applied to the case of PtRh/Al{sub 2}O{sub 3} catalysts. The study of monometallic model catalysts shows that the adsorption of NO at 473 K on rhodium gives an intense band at 1912 cm{sup {minus}1} which is not modified by the presence of ceria and therefore can be used to quantify the number of surface rhodium atoms. However, the chemisorption properties of platinum toward the subsequent adsorption of CO at 298 K are strongly modified and the quantification of the surface platinum atoms could not be directly measured. However, their number could be indirectly obtained by combining the NO adsorption for rhodium and hydrogen volumetric adsorption for the total number of surface metal atoms, assuming that NO adsorption does not induce an important segregation of rhodium for bimetallic particles. Thus, for the fresh bimetallic model catalyst, the same composition was obtained at the surface and in the bulk. After aging at 1273 K, no rhodium was detected at the surface. This absence of surface rhodium atoms was confirmed by the data obtained from the direct adsorption of CO on platinum at room temperature, which gave the same number of surface atoms as hydrogen chemisorption. Similar results have been obtained with two commercial three-way catalysts. In particular, after aging at 1273 K, rhodium was practically not detected on the surface.},
doi = {10.1006/jcat.1999.2585},
journal = {Journal of Catalysis},
number = 2,
volume = 186,
place = {United States},
year = {1999},
month = {9}
}