A New Strategy in Heterogeneous Catalysis: The Design of Cortex Catalysts

Without appreciable migration into the pores of the support (Al2O3), preformed and size-selectively synthesized metal clusters (e.g. Pd or Ni) and bimetal clusters (e.g. Pt/Sn) stabilized by ammonium salts can be placed specifically on the outer surface and immobilized (see schematic representation on the right; black: metal cluster, gray: support particles). Initial experiments indicate that such cortex catalysts show increased activities in hydrogenation reactions.