ONSET OF PEROVSKITE FORMATION IN THE CATALYTIC-SYSTEM LA2O3 GAMMA-AL2O3/

Molecular dynamics simulations of model systems for the surface intera ction of lanthanum oxide supported on gamma-alumina have been carried out at 1500 K. The onset of formation of perovskite-like phases has be en analysed in samples containing four different concentrations of lan thanum oxide. A mechanism of the formation of perovskite-like polyhedr a is proposed. This mechanism essentially involves a displacement of a n oxide ion associated to an octahedral aluminum by a lanthanum ion an d appears to be independent of La2O3 loadings.