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In Situ Optical Reflectance Difference Observations of CO Oxidation over Pd(100).
Onderwaater, Willem G; Taranovskyy, Andriy; van Baarle, Gertjan C; Frenken, Joost W M; Groot, Irene M N.
Afiliação
  • Onderwaater WG; Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
  • Taranovskyy A; European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex 9, France.
  • van Baarle GC; Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
  • Frenken JWM; Leiden Probe Microscopy B.V., J.H. Oortweg 19, 2333 CH Leiden, The Netherlands.
  • Groot IMN; Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
J Phys Chem C Nanomater Interfaces ; 121(21): 11407-11415, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28603579
ABSTRACT
Using a home-built reflectometer, we have investigated the changes in the optical reflectivity of a Pd(100) model catalyst during CO oxidation under high-pressure, high-temperature conditions. We observe changes in optical contrast when exposing the surface to CO oxidation conditions at 200 mbar from room temperature up to 400 °C. These changes in reflectivity are a result both of the formation of a surface oxide layer and of a change in surface roughness because of gas exposure. However, the reflectivity is more sensitive to the presence of a thin, flat oxide layer than to surface roughness. CO oxidation plays an important role in the decrease of the reflectivity. Since adding a reducing agent to the gas mixture renders it unlikely that the oxide thickness increases, we conclude that the observed decrease in reflectivity is dominated by increased surface roughness because of the catalytic reaction. We contribute this observed surface roughening to a Mars-van Krevelen-type reaction mechanism.

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Texto completo: Disponível Coleções: Bases de dados internacionais Base de dados: MEDLINE Idioma: Inglês Revista: J Phys Chem C Nanomater Interfaces Ano de publicação: 2017 Tipo de documento: Artigo País de afiliação: Holanda