Onset of perovskite formation in the catalytic system La2O3/?-Al2O3

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