Prof. Ferdi Schüth – MPI für Kohlenforschung:

Over the last decades, tremendous progress has been made in the control of catalytic materials on the nanometer size scale. This includes tailoring of pore sizes of catalytic materials by different soft and hard templating techniques, size control of catalytically active metal particles by solution phase synthesis of such particles and subsequent deposition on supports, the placement of catalytic particles in desired locations of structured support materials, and the design of solid environments which resemble ligand motifs of molecular catalysts.

A survey will be given on different methods to create defined pore systems in various materials. The placement of catalytically active particles in desired locations of such structured supports will be discussed for several examples. Encapsulation of single metal particles in hollow shells made of zirconia, titania or carbon allows the synthesis of catalysts which are stable against sintering, since individual particles are encapsulated and therefore can not migrate towards each other, which prevents sintering. This pathway is highly flexible, if the parameters are fine-tuned, and a wide range of catalysts is accessible. Alternatively, if platinum particles are deposited in the mesopores of the shell, the platinum dispersion is thermally extremely stable, and the materials are highly interesting fuel cell catalysts. Ordered mesoporous materials also allow controlled placement of particles in the pores, and the resulting solids are suitable as high performance catalysts and in lithium ion batteries, for instance.

Finally, the synthesis of solids having ligand motifs of the Periana catalyst for the oxidation of methane to methylbisulfate (which can be hydrolyzed to methanol) has recently become possible. Such solids can be impregnated with suitable platinum species, upon which solid analogues to the Periana system result, with comparable catalytic activity for methane oxidation. This concept might be extendable to other catalytic systems so that a new range of solid catalysts could be synthesized.