Dispersed metal particles in zeolite carriers

This paper is a review of the recent works on the formation and properties of metallic aggregates dispersed into the zeolite structures. The most important contribution concerns the faujasites and the precursors cations belonging to the group VIII. The conditions of formation of highly dispersed particles are defined particularly in the case of precursor cations poorly reducible. When the environment of the reducible cations is modified by the variation of Si/Al ratio or by the introduction of non reducible Cocations, the aggregates formation and their stability are also modified. Some results on the electronic state of small aggregates are reported