SIMULATION OF THERMAL-DESORPTION FROM NANOMETER CATALYST PARTICLES

General equations are derived to describe monomolecular desorption fro m small supported catalyst particles in the cases where (i) the desorp tion process occurs simultaneously from different facets and (ii) adso rbed molecules are allowed to jump from the catalyst onto the support, diffuse on the support, and then desorb (a so-called spillover effect ). Numerical calculations carried out on the basis of obtained equatio ns indicate that the TPD spectra for interconnected facets might be qu alitatively different from those for extended single crystals. The sup port-mediated channel has been shown to be important if the binding en ergy on the support is not too low.