The study of diffusion processes in the thermodesorption results

Abstract

A consecutive model of surface reaction, consisting of two steps (desorption and diffusion) was applied. It was concluded that diffusion modifies the temperature programmed desorption spectra, although the single peak curves appear. The differential method for calculation of kinetic parameters based on the sTM shift give values close to predicted ones only in the cases when particular steps are rate limiting. Generally, the desorption process have to be considered as a complex reaction, with the overall kinetic parameters. As a consequence of diffusion influence, the overall kinetic parameters are smaller than those for desorption step was obtained. © 1992 Wiley Heyden Ltd, Chichester and Akadémiai Kiadó, Budapest.