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Superior catalytic behaviour of Pt-doped Pd catalysts in the complete oxidation of methane at low temperature 总被引:1,自引:0,他引:1
G. Lapisardi L. Urfels P. Glin M. Primet A. Kaddouri E. Garbowski S. Toppi E. Tena 《Catalysis Today》2006,117(4):564-568
The catalytic combustion of methane at low temperature under lean conditions was investigated over bimetallic palladium-platinum catalysts supported on alumina. Pd-Pt catalysts with constant 2 wt.% metal loading and varying compositions in Pt and Pd were prepared by successive impregnations of the metal salts. The catalysts were characterised by powder X-ray diffraction, transmission electron microscopy/electron dispersion X-ray spectroscopy (TEM/EDX), volumetry of H2 chemisorption, FTIR study of CO adsorption and temperature-programmed oxidation (TPO). In the absence of water added to the feed, the methane conversion over Pd-rich bimetallic catalysts (Pt/Pt + Pd molar ratios less than 0.3) was found to be the same as that of the reference Pd/Al2O3 catalyst. Interestingly, under wet conditions, these bimetallic catalysts exhibited an improved performance with respect to Pd/Al2O3. This effect was found to be maintained upon mild steam ageing. An interaction between both metals was suggested to explain the enhanced activity of bimetallic catalysts. This was confirmed by TPO experiments indicating that formation and decomposition of PdO is affected upon Pt addition even for very low amounts of Pt. The adsorption of CO on reduced catalysts studied by FTIR revealed new types of adsorbed CO species, suggesting again an interaction between two metals. 相似文献
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Lapisardi G. Gélin P. Kaddouri A. Garbowski E. Da Costa S. 《Topics in Catalysis》2007,42(1-4):461-464
Bimetallic Pd–Pt catalysts with constant 2 wt% metal loading and varying Pt/Pd ratios were prepared, characterized and studied
in the catalytic combustion of methane at low temperature under lean conditions in view of their use for CH4 abatement from lean-burn NGV heavy duty vehicles exhausts. The influence of mild steam ageing featuring long-term use of
the catalysts was also addressed together with their tolerance to H2S. Catalysts were characterised by Transmission Electron Microscopy and Temperature Programmed Oxidation experiments. Experimental
data agreed to suggest an interaction between Pd and Pt in Pd-rich catalysts, thus explaining their improved catalytic activity,
even after mild ageing, compared to reference Pd/Al2O3. This interaction has no effect on the sulfur tolerance. 相似文献
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