Diffusion-limited reaction kinetics in nanofabricated porous model catalysts

Electron beam lithography makes it possible to fabricate ideal, representative models of supported, porous catalysts (with pore and particle dimensions and separations of ~10 nm and up). This allows systematic exploration of various scientifically and technically important phenomena associated with porous, supported catalysts. In the present work, we have derived general equations describing the reaction kinetics on such model catalysts in combination with mass-transport corrections. Depending on the geometrical parameters and boundary conditions the reaction rate may be limited by bulk or Knudsen diffusion of reactants inside pores or by diffusion in the regions near or far from the support surface. All these regimes are treated in detail. The results will help both to guide and interpret experiments with nanofabricated catalysts.