Premium
Temperature‐programmed desorption: Multisite and subsurface diffusion models
Author(s) -
Leary K. J.,
Michaels J. N.,
Stacy A. M.
Publication year - 1988
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690340210
Subject(s) - desorption , diffusion , adsorption , thermal desorption spectroscopy , catalysis , surface diffusion , chemistry , thermodynamics , analytical chemistry (journal) , chemical engineering , chemical physics , chromatography , physics , organic chemistry , engineering
Two models are presented that can simulate two peaks in a temperature‐programmed desorption (TPD) spectrum from a high surface area catalyst at atmospheric pressure: a multisite model and a subsurface diffusion model. The multisite model assumes that the two peaks arise from two distinct adsorption sites on the catalyst surface with different activation energies for desorption. The subsurface diffusion model assumes that the high‐temperature peak is produced by adsorbate that diffuses into the subsurface region of the catalyst during heating, and then back to the surface when it becomes depleted by the desorption process. It is shown that one can distinguish between the two models experimentally by measuring the effect of carrier gas flow rate and heating rate on the TPD spectrum.