Ln. Ikryannikova et al., The red-ox treatments influence on the structure and properties of M2O3-CeO2-ZrO2 (M = Y, La) solid solutions, APP CATAL A, 210(1-2), 2001, pp. 225-235
The introduction of trivalent cation - Y3+ or La3+ - into the lattice of Ce
O2-ZrO2 solid solutions allows to stabilise a cubic structure at low ceria
content (30 mol%). The reducibility of the samples has been compared in the
experiments of temperature-programmed reduction (TPR). Thr introduction of
lanthanum cations decreases the amount of hydrogen consumed during TPR, wh
ile the introduction of yttrium ones increases this value. At the same time
, the value of temperature of the maximum speed of reduction (T-max) is ind
ependent on the trivalent dopant. The reducibility of these solid solutions
did not change during repeated red-ox treatments at temperature below 1220
K. It is connected with the high thermostability of all systems in this te
mperature interval. TPR up to 1470 K causes a significant shift of T-max va
lue to higher temperature and a slight decrease of hydrogen consumption in
two to three cycles. It is suggested that this alterations are connected wi
th the sharp decrease of the specific surface area of all samples and parti
ally phase decomposition of CeO2-ZrO2 and Y2O3-CeO2-ZrO2 solid solutions. R
aman characterisation of the oxygen sublattice of the fresh samples and of
the samples after TPR has been carried out. (C) 2001 Elsevier Science B.V.
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