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Pd Loading and Structure of Flame-Made Pd/YFeO3±δ

Lu, Ye ; Keav, Sylvain ; Maegli, Alexandra ; Weidenkaff, Anke ; Ferri, Davide

In: Topics in Catalysis, 2015, vol. 58, no. 14-17, p. 910-918

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    Title
    • Pd Loading and Structure of Flame-Made Pd/YFeO3±δ
    Author
    • Lu, Ye. Laboratory for Solid State Chemistry and Catalysis, Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
    • Keav, Sylvain. Laboratory for Solid State Chemistry and Catalysis, Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
    • Maegli, Alexandra. Laboratory for Solid State Chemistry and Catalysis, Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
    • Weidenkaff, Anke. Laboratory for Solid State Chemistry and Catalysis, Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
    • Ferri, Davide. Paul Scherrer Institut, 5232, Villigen, Switzerland
    Document Type
    • Postprint
    Language
    • English
    Published in
    • Topics in Catalysis, 2015, vol. 58, no. 14-17, p. 910-918. Springer US; http://www.springer-ny.com
    Other Version
    OAI-PMH Identifier
    • oai:doc.rero.ch:332883
    Summary
    The interactions between a platinum-group metal (PGM) and a perovskite-type oxide are complex since the latter can accommodate the former in its structure, simply act as a support or, in specific cases, reversibly switch between these two behaviours, depending on the redox environment. Despite promising performances as oxidation catalysts, Y-based perovskite-type oxides are far less studied than their La-based counterparts and their interactions with PGM need to be better understood. The morphology, coordination and oxidation state of Pd species in Pd-doped YFeO3±δ catalysts prepared by flame spray synthesis were investigated in dependence on Pd loading in the range of 0-2.5wt%. Their thermal stability was assessed by calcination of the flame-made materials at 700°C. Fresh and calcined samples were thoroughly characterized by STEM, N2-physisorption, XRD, XPS, DRIFTS and OSCC. Pd species were predominantly in the form of metallic nano-particles supported on YFeO3±δ. The size of these nano-particles increased with increasing loading as evidenced by DRIFTS. XPS facilitated the identification of Pd2+ species in strong interaction with the hexagonal YFeO3 lattice, suggesting the partial incorporation of noble metal ions in the perovskite-type structure. After calcination at 700°C, this contribution vanished in the catalysts containing at least 2 wt% Pd. The catalysts were tested for methane oxidation under stoichiometric conditions up to 850°C. The catalyst with 2 wt% Pd exhibited the highest CH4 oxidation activity. Reduction of the Pd content to 0.5 wt% resulted in the shift of the 50% CH4 conversion by only ca. 40°C. Hence, flame-made Pd/YFeO3±δ demonstrated to be a suitable material to maintain CH4 conversion with reduced noble metal content.