Y. Yasuda et E. Kuno, NOVEL KINETIC-MODEL FOR HETEROGENEOUS CATALYSIS BASED ON FREE-ENERGY DISSIPATION VIA INTERMEDIATES DEDUCED BY THE FREQUENCY-RESPONSE METHOD, The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 102(25), 1998, pp. 4878-4882
A novel kinetic model for heterogeneous catalysis based on the flow of
free energy (instead of ordinary mass-flow) is proposed; the chemical
kinetic model is valid to interpret a ''reaction-rate spectrum'' obta
inable by a frequency response (FR) technique. The characteristic func
tion to analyze the spectrum derived from the kinetic differential equ
ations contains complex rate constants, (k + i omega l)'s; k denotes t
he ordinary rate constant at an elementary step, l is the novel rate c
onstant due to the free energy dissipation, and omega is the angular f
requency scanned in the FR technique. The conclusion has been confirme
d by actual data obtained in a catalytic hydrogenation of propene over
Pt and/or Rh metals on the basis of a three-stage model: X(g) reversi
ble arrow A(X)(a) reversible arrow B-X(a) --> Product(s), where X(g) r
epresents propene or hydrogen molecules in the gas phase; A(X)(a) and
B-X(a) are the intermediates on the catalysts. This model contains fiv
e k's for the three direct and two reverse reactions and two l's of A(
X) and B-X for their two direct reactions. On the basis of the present
results, a generic procedure to analyze a reaction-rate spectrum is p
roposed.