Polysiloxane-Derived Ceramics Containing Nanowires with Catalytically Active Tips

By direct foaming of a Pt‐containing polysiloxane precursor, macroporous ceramics were generated by pyrolysis at 1400°C under nitrogen or argon. The growth of nanowires was induced via a vapor–liquid–solid mechanism in which the Pt particles acted as deposition site for the decomposition gases relea...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 2014-03, Vol.97 (3), p.959-966
Main Authors: Adam, Michael, Vakifahmetoglu, Cekdar, Colombo, Paolo, Wilhelm, Michaela, Grathwohl, Georg
Format: Article
Language:English
Subjects:
Ceramics
Decomposition
Gases
Liquid crystal polymers
Nanowires
Oxidation
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Summary:By direct foaming of a Pt‐containing polysiloxane precursor, macroporous ceramics were generated by pyrolysis at 1400°C under nitrogen or argon. The growth of nanowires was induced via a vapor–liquid–solid mechanism in which the Pt particles acted as deposition site for the decomposition gases released upon pyrolyzing the preceramic polymer. SEM, HR‐SEM, TEM/EDX, and XRD investigations revealed that pyrolysis under argon atmosphere leads to short SiC nanowires of only a few micrometers length and under nitrogen atmosphere Si3N4 nanowires evolved, with length of several 10 μm. In both cases the tips of the nanowires mainly consisted of PtSi. In contrast to samples pyrolyzed at 600°C, the components after higher temperature pyrolysis showed moderate‐specific surface areas of 55–67 m2/g. In CO oxidation experiments, a good catalytic activity was found for the Pt silicide particles, suggesting that despite their relatively large size, their location at the tips of the nanowires affords them good reactivity.
ISSN:0002-7820
1551-2916
DOI:10.1111/jace.12708