A theoretical investigation of the adsorption surface sites of the activated MgCl2

The adsorption of carbon monoxide on activated MgCl₂ has been investigated within DFT using different models of the MgCl₂ surface. All the models were Mg₆Cl₁₀ clusters with two saturating OH groups. It has been found that the adsorption sites within the models based on the geometry of the ideal MgCl₂ crystal are stronger than they are in the experiment. It has also been found that relaxed clusters based on the geometry of the relaxed MgCl₂ surface present more accurate models of the MgCl₂ surface and account the relaxation effects properly. IR spectra of carbon monoxide bounded to three different adsorption sites calculated within relaxed clusters approximation is in excellent agreement with the experimental data. Such an agreement allows us to conclude that adsorption sites of the activated MgCl₂ surface in general are 3-, 4- and 5-fold Mg atoms and the structure of these sites follows the structure of corresponded relaxed MgCl₂ crystallographic faces.