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Determination of rate constants by the frequency response method: CO on Pt/SiO 2
Author(s) -
Li YaoEn,
Willcox David,
Gonzalez Richard D.
Publication year - 1989
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.690350310
Subject(s) - adsorption , desorption , reaction rate constant , analytical chemistry (journal) , chemistry , catalysis , thermodynamics , phase (matter) , kinetics , chromatography , physics , organic chemistry , quantum mechanics
A technique based upon transmission FTIR to obtain rate constants for adsorption and desorption over supported metal catalysts has been developed and tested. The technique requires the use of a sinusoidal perturbation function imposed on steady state linearized adsorption‐desorption kinetics. The measurement of a phase lag between the sinusoidal inlet gas phase forcing concentration and the response of surface coverage, together with a measurement of the maximum amplitudes of the forcing function and surface response enable the calculation of the relevant adsorption and desorption rate constants. The technique has been successfully applied to the measurement of both adsorption and desorption rate constants for CO adsorbed on a 1% Pt/SiO 2 catalyst. The values obtained for these rate constants at 343 K were: K a = 0.147 s −1 and K d = 7.28 × 10 −3 s −1 . A sticking coefficient corresponding to the adsorption of weakly bonded CO on Pt under conditions of high CO surface coverage was obtained.