Oxygen exchange on nanocrystalline tin dioxide modified by palladium

D. D. Frolov, Y. N. Kotovshchikov, I. V. Morozov, A. I. Boltalin, A. A. Fedorova, A. V. Marikutsa, M. N. Rumyantseva, A. M. Gaskov, E. M. Sadovskaya, A. M. Abakumov

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39 Citations (Scopus)

Abstract

Temperature-programmed oxygen isotopic exchange study was performed on nanocrystalline tin dioxide-based materials synthesized via solgel route and modified by palladium. Such materials are widely used as resistive gas sensors. The experiments were carried out in a flow-reactor up to complete isotopic substitution of oxygen. Substantial rates of isotopic exchange for SnO 2 were observed from about 700 K. The distribution of isotopic molecules 16O 2, 16O 18O and 18O 2 corresponds to simple dioxygen heteroexchange mechanism with single lattice oxygen atom. The modification of SnO 2 by Pd introduced multiple heteroexchange mechanism with preliminary O 2 dissociation on the clusters surface. Spill-over of atomic oxygen from Pd to the surface of SnO 2 and fast exchange with lattice oxygen result in more than 100% increase of apparent heteroexchange rate. The exchange on SnO 2/Pd was shown to be a complex process involving partial deactivation of the catalytic centers at temperature higher than 750 K.

Original languageEnglish
Pages (from-to)1-8
Number of pages8
JournalJournal of Solid State Chemistry
Volume186
DOIs
Publication statusPublished - Feb 2012
Externally publishedYes

Keywords

  • Heteroexchange
  • Nanocrystalline tin dioxide
  • Oxygen diffusion
  • Oxygen isotopic exchange
  • Palladium

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