Polysiloxane- derived ceramics containing nanowires with catalytically active tips
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Tarih
2014
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Wiley-Blackwell
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
By direct foaming of a Pt-containing polysiloxane precursor, macroporous ceramics were generated by pyrolysis at 1400 degrees 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 10m. In both cases the tips of the nanowires mainly consisted of PtSi. In contrast to samples pyrolyzed at 600 degrees C, the components after higher temperature pyrolysis showed moderate-specific surface areas of 55-67m(2)/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.
Açıklama
Vakifahmetoglu, Cekdar/0000-0003-1222-4362; Wilhelm, Michaela/0000-0001-8651-1546
Anahtar Kelimeler
Active Tips
Kaynak
Journal of the American Ceramic Society
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
Cilt
97
Sayı
3
