Volume 9, Issue 18 p. 3544-3553
Full Paper

Three-Dimensional Probing of Catalyst Ageing on Different Length Scales: A Case Study of Changes in Microstructure and Activity for CO Oxidation of a Pt–Pd/Al2O3 Catalyst

Torben Nilsson Pingel

Corresponding Author

Torben Nilsson Pingel

Competence Centre for Catalysis, Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden

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Dr. Sheedeh Fouladvand

Dr. Sheedeh Fouladvand

Competence Centre for Catalysis, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Gothenburg, Sweden

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Dr. Marc Heggen

Dr. Marc Heggen

Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Jülich Research Centre, 52425 Jülich, Germany

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Prof. Rafal E. Dunin-Borkowski

Prof. Rafal E. Dunin-Borkowski

Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Jülich Research Centre, 52425 Jülich, Germany

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Prof. Wolfgang Jäger

Prof. Wolfgang Jäger

Competence Centre for Catalysis, Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden

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Peter Westenberger

Peter Westenberger

FEI—Visualization Sciences Group, 40237 Düsseldorf, Germany

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Daniel Phifer

Daniel Phifer

FEI—Science Group, 5651 GG, Eindhoven, The Netherlands

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Jace McNeil

Jace McNeil

FEI—Hillsboro, 97124 OR, USA

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Prof. Magnus Skoglundh

Prof. Magnus Skoglundh

Competence Centre for Catalysis, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Gothenburg, Sweden

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Prof. Henrik Grönbeck

Prof. Henrik Grönbeck

Competence Centre for Catalysis, Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden

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Prof. Eva Olsson

Prof. Eva Olsson

Competence Centre for Catalysis, Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden

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First published: 23 March 2017
Citations: 2

Graphical Abstract

Look inside! A bimetallic Pt–Pd/Al2O3 oxidation catalyst is investigated by electron microscopic techniques, revealing its three-dimensional nano- and microstructure. Thermal treatments have a great impact on the microstructure and activity for CO oxidation.

Abstract

The effects of thermal treatment on the microstructure of a Pt–Pd/Al2O3 oxidation catalyst and its activity for CO oxidation have been studied. The microstructural analysis was performed by using several high-resolution electron microscopy techniques such as STEM, FIB/SEM slice & view, SEM and EDX. A combination of these analytic techniques and advanced TEM specimen preparation allowed for three-dimensional probing at different length scales, avoiding the random character of conventionally crushed powder specimens owing to site specificity. A core–shell distribution of Pt–Pd nanoparticles within the alumina support particles, with enlarged nanoparticles (≈1.5 to 40 nm) present in the shell and small nanoparticles (<1.5 nm) in the core, was revealed in the untreated catalyst. A more uniform spatial distribution developed during thermal treatment at 700 °C or higher with larger nanoparticles forming in the core. Accompanying measurements of the catalytic activity for CO oxidation showed the detrimental effect of sintering of the small nanoparticles on the reaction rate and apparent activation energy of the reaction.

Conflict of interest

The authors declare no conflict of interest.