Rare earth oxide aero- and xerogels tuning porosity and catalytic properties

Metal oxide catalysts represent an important part of available heterogeneous catalysts. They may be used as support materials e.g. for metal catalysts or as in my own work represent themselves the active phase of the catalyst. In addition to the nature of the specific surface chemistry, the structure of the catalyst - and in particular the porosity - plays a highly important role. This is due to the fact that diffusion of reactants educts and products can influence the overall rate and thus catalyst efficiency, if the transport rather than the reaction is rate limiting. We speak of mass transport limitation then. Many traditional catalyst preparation techniques do not allow the optimization of the active phase and the overall porous structure independently so that the concomitant optimization of both factors is often difficult to realize.