ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
Nanocrystalline CeO2-ZrO2 (Ce:Zr 1:1) samples doped with La, Pr or Gd cations(containing up to 30 at.%) were prepared via the Pechini route. Pt (1.4 wt.%) was supported viaimpregnation with H2PtCl6 solution followed by drying and calcination. The samples’ surfacefeatures were studied by SIMS and FTIRS of adsorbed CO. The oxygen mobility was characterizedby the dynamic oxygen isotope exchange and H2 TPR. Catalytic activity was studied in the flowinstallation using diluted feeds (0.7% CH4 +0.5% O2 or 1% C3H6O + 0.5% O2 +0.5% H2O in He).In the selective oxidation of methane (POM), the catalytic activity correlates with Pt dispersioncontrolled by the oxidized sample’s ability to stabilize Pt2+ cations as precursors of small reactive Ptclusters formed under reaction conditions. This is favoured by a larger doping cation (La) and adeveloped network of nanodomain boundaries. At comparable Pt dispersion, the highestperformance was demonstrated by a La-doped system, which correlates with the highestsurface/near-surface oxygen mobility controlled by the strength of Ce-O bonds in the surface layer.In the autothermal reforming of acetone, the activity trends differ from those in POM because of themore prominent role of the oxygen mobility required to prevent surface coking
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.128.239.pdf
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