A few perovskite-like and fluorite-like samples in which M=Pr, Sm or Tb substitutes for La have been characterised by electron magnetic resonance (EMR) spectroscopy and other techniques. Ferromagnetic (FM) systems form with the fresh biphasic sample with M =Sm only, but not after recalcination, when it becomes monophasic. These systems could be formed of Magnetic Bound Polarons due to the thermally excited J=1 Sm2+ ions present as impurity in the former case. FM systems form also with the M = Tb sample, but only after catalytic use. In this case FM systems could be composed of Tb4+ ions forming during sample re-oxidation. All these EMR observations have been correlated with the catalytic performance of these samples.
EMR characterisation of La1.8M0.2CuO4 and La0.9M0.1CoO3 (M = Pr, Sm, Tb) catalysts for methane flameless combustion / C. Oliva, S. Cappelli, A. Kryukov, G.L. Chiarello, A.V. Vishniakov, L. Forni. - In: JOURNAL OF MOLECULAR CATALYSIS. A: CHEMICAL. - ISSN 1381-1169. - 247:1-2(2006), pp. 248-252.
EMR characterisation of La1.8M0.2CuO4 and La0.9M0.1CoO3 (M = Pr, Sm, Tb) catalysts for methane flameless combustion
C. OlivaPrimo
;S. CappelliSecondo
;G.L. Chiarello;L. ForniUltimo
2006
Abstract
A few perovskite-like and fluorite-like samples in which M=Pr, Sm or Tb substitutes for La have been characterised by electron magnetic resonance (EMR) spectroscopy and other techniques. Ferromagnetic (FM) systems form with the fresh biphasic sample with M =Sm only, but not after recalcination, when it becomes monophasic. These systems could be formed of Magnetic Bound Polarons due to the thermally excited J=1 Sm2+ ions present as impurity in the former case. FM systems form also with the M = Tb sample, but only after catalytic use. In this case FM systems could be composed of Tb4+ ions forming during sample re-oxidation. All these EMR observations have been correlated with the catalytic performance of these samples.Pubblicazioni consigliate
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