The Active Phase of Palladium during Methane Oxidation.
The active phase of Pd during methane oxidation is a long-standing puzzle, which, if solved, could provide routes for design of improved catalysts. Here, density functional theory and in situ surface X-ray diffraction are used to identify and characterize atomic sites yielding high methane conversion. Calculations are performed for methane dissociation over a range of Pd and PdOx surfaces and reveal facile dissociation on either under-coordinated Pd sites in PdO(101) or metallic surfaces. The experiments show unambiguously that high methane conversion requires sufficiently thick PdO(101) films or metallic Pd, in full agreement with the calculations. The established link between high activity and atomic structure enables rational design of improved catalysts.
†Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96, Göteborg, Sweden.
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Hellman
‡ESRF, 6 rue Jules Horowitz -38000 Grenoble, France.
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Resta
§Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 00, Sweden.
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Martin
§Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 00, Sweden.
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Gustafson
†Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96, Göteborg, Sweden.
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Trinchero
†Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96, Göteborg, Sweden.
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Carlsson
‡ESRF, 6 rue Jules Horowitz -38000 Grenoble, France.
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Balmes
‡ESRF, 6 rue Jules Horowitz -38000 Grenoble, France.
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Felici
‡ESRF, 6 rue Jules Horowitz -38000 Grenoble, France.|∥Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
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van Rijn
∥Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
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Frenken
§Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 00, Sweden.
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Andersen
§Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 00, Sweden.
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Lundgren
†Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96, Göteborg, Sweden.
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Grönbeck
Pd; PdO; active phase; density functional theory; methane oxidation; surface X-ray diffraction