Journal of Physical Chemistry, Vol.100, No.44, 17613-17620, 1996
Density-Functional Study of Oxygen Sorption in Cyanocobaltate Complexes - Reversibility and Charge-Transfer
We present a theoretical study using density functional theory on O-2 sorption by cyanocobaltate complexes. A cluster model that encompasses the cyanocobaltate species linked with various cations, including Mg2+ H+, Li+, Na+, and K+, is employed to describe the O-2 sorption phenomena by these sorbents. We show that the present model and computational methods are capable of providing essentially quantitative information about the sorption reversibility. The calculated geometric structures, vibrational frequencies, and sorption binding energies are in good agreement with the available experimental results. The predicted sorption properties are consistent with our experimental observations, The present calculations confirmed the previously proposed hypothesis that O-2 sorption reversibility in these materials can be controlled by the cations through an electron withdrawal process, We show that the sorption binding energy increases as the electron-withdrawing capability of the cations decreases. The O-2 sorption reversibility in these sorbents is characterized through several important physical quantities.
Keywords:REACTIVITY;BINDING