Modified tin(IV) oxide (M/SnO{sub 2} M = Cr, La, Pr, Nd, Sm, Gd) catalysts for the oxidation of carbon monoxide and propane
- Univ. of Nottingham (United Kingdom). School of Chemistry
Materials formed by the incorporation of rare earth cations (M = La, Pr, Nd, Sm, Gd) into tin(IV) oxide using coprecipitation methods show no significant enhancement of catalytic activity toward the oxidation of carbon monoxide or propane over that of tin(IV) oxide itself. For chromium-promoted tin(IV) oxide catalysts, the temperature by which complete conversion of carbon monoxide and propane occurs is dependent on both the Cr:Sn atom ratio in the catalyst and the preparative route by which the chromium is incorporated into the catalyst. As prepared all the materials are hydrous gels comprising very small (<10 nm) particles of tin(IV) oxide over which the modifying metal component appears to be dispersed uniformly. Chromium(VI) oxyanions of the types CrO{sub 4}{sup 2{minus}}, Cr{sub 2}O{sub 7}{sup 2{minus}}, and Cr{sub 3}O{sub 10}{sup 2{minus}} are sorbed on to the surface of the tin(IV) oxide particles in the freshly prepared material derived from aqueous CrO{sub 3} and tin(IV) oxide gel. Prior to calcination the materials are microporous, but significant changes in specific surface area, pore volume, and pore size occur at temperature >673 K. Powder X-ray diffraction and electron microscopy confirm the formation of Cr{sub 2}O{sub 3} on calcination at K.
- OSTI ID:
- 687731
- Journal Information:
- Journal of Catalysis, Vol. 186, Issue 1; Other Information: PBD: 15 Aug 1999
- Country of Publication:
- United States
- Language:
- English
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