Catalytic oxidation of carbon monoxide over superconducting and related cuprates
1992; Elsevier BV; Volume: 134; Issue: 2 Linguagem: Inglês
10.1016/0021-9517(92)90356-m
ISSN1090-2694
AutoresI. Halász, Alan Brenner, M. Shelef, K. Y. Simon Ng,
Tópico(s)Physics of Superconductivity and Magnetism
ResumoA series of palladium-substituted La2CuO4, corresponding to the formula La2Cu1 −xPdxO4 (x = 0−0.2) were prepared by metal nitrate decomposition in a polyacrylamide gel. This method allows an easy incorporation of palladium in the mixed-oxides, which are formed at moderate temperature with rather high specific areas (13–17 m2/g). The partial substitution of copper for palladium allows a strong improvement of the three-way catalytic activity, in particular for NO reduction. The light-off temperatures for the conversions of CO, NO and C3H6 decreased markedly when increasing the palladium content, the activity of catalysts La2Cu0.9Pd0.1O4 and La2Cu0.8Pd0.2O4 being comparable to that of a Pt-Rh/CeO2–Al2O3 catalyst for NO reduction, and higher for CO and C3H6 oxidation.All the La2Cu1 − x PdxO4 catalysts are activated under reacting conditions. This activation corresponds to the destruction of the mixed-oxide structure, with formation of reduced Pd0 ions atomically dispersed, surrounded by Cu+ and Cu2+ species on a lanthanum oxycarbonate matrix. This high dispersion state of the two transition metals in various oxidation states is supposed to originate from the initial La2Cu1 −xPdxO4 structure.
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