P 03/02


Catalytic active Materials prepared from Sol-Gel techniques

his project focuses on sol gel techniques, especially stable colloidal solutions (sols), for the preparation of xerogels catalysts and coatings for highly exothermic catalytic gas phase reactions. In comparison to conventional pellet catalysts, a lower pressure drop and a better heat/mass transport can be realized by using open porous monolithic supports. In comparison to classical incipient wetness methods, the active phase and the support are directly formed during calcination, which often results in highly dispersed, supported particles, controllable metal-support interactions and a high porosity. The primary aim is the preparation and testing of catalysts powders and coatings for the Fischer-Tropsch synthesis. In case of coatings, metallic as well as ceramic foams will be subject of the research. Within the sol gel approach colloidal particles in the nm range are stabilized in a proper solvent. From these sols, thin layers in the range of 1 to 10 µm can be coated. In comparison to the conventional suspension approach, the active phase is formed directly on the support, which offers good adhesive properties. Furthermore, the blocking of pores can be avoided due to the small particle size and the low solid-phase content. In cooperation with the work group from Prof. Thöming we target the investigation of mass- and heat-transport effects as a function of the structural properties and of the activity and selectivity as a function of the chemical composition of powders and in particular coated monolithic samples in small lab scale experiments up to small pilot plants.

Contact: Bäumer , Ilsemann