Composition including a lanthanum perovskite on an alumina or aluminium oxyhydroxide substrate, preparation method and use in catalysis

摘要

A composition is described that includes a perovskite of the formula LaMO3, where M is at least one element selected from among iron, aluminum or manganese, in the form of particles dispersed on an alumina or aluminum oxyhydroxide substrate, wherein after calcination at 700° C. for 4 hours, the perovskite is in the form of a pure crystallographic phase, and in that the size of the perovskite particles does not exceed 15 nm. The described composition can be used in the field of catalysis.

主权项

1. A process for the preparation of a calcined composition comprising
a perovskite having formula LaMO3 in which M represents at least one element chosen from iron, aluminum, or manganese, in the form of particles, a support based on alumina or aluminum oxyhydroxide, that has been precalcined at a temperature between greater than 500° C. and less than 700° C., and optionally a substituent element partially substituting at least one of the elements La and M of the perovskite,wherein the perovskite particles are dispersed over the support, and wherein, after calcination at 700° C. for 4 hours, the perovskite exists in the form of a pure crystallographic phase and the perovskite particles have a size of at most 15 nm, wherein the process comprises:
forming a liquid medium comprising:
alumina or aluminum oxyhydroxide that has been precalcined at a temperature between greater than 500° C. and less than 700° C.;salts of the elements La and M;and optionally, a substituent element partially substituting at least one of the elements La and M; adding a base to the medium thus formed until a pH of at least 9 is obtained, thereby forming a precipitate; separating the precipitate from the medium; and calcining the precipitate to obtain the composition.