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.

Graphical abstractThe adsorption of carbon monoxide on activated MgCl2 has been investigated within DFT using different models of the MgCl2 surface. It has been found that proposed model based on the geometry of the relaxed MgCl2 surface allows to simulate the IR bands of the adsorbed CO within the accuracy better than 10 cm−1. A new model of the adsorption surface sites of the activated MgCl2.Figure optionsDownload full-size imageDownload as PowerPoint slide