Adsorption of CS_2 on MgO microcrystals: formation of a S-doped MgO surface

摘要

The interaction of carbon disulfide, CS_2, with polycrystalline MgO was investigated by means of infrared and UV-visible spectroscopies and ab initio electronic structure calculations. The aim was to understand the modifications of the surface properties of MgO microcrystals induced by the substitution of O~(2-) with S~(2-) anions. The interaction of CS_2 with MgO shows the formation of thiocarbonates followed by O-S exchange reactions and formation of Mg~(2+)-S~(2-) clusters in a MgO matrix. The O-S exchange reaction invovles mainly the low-coordinated O~(2-) anions at the (100) terrace sites involved. The replacement of the O with the S atoms at low-coordinated sites of the MgO surface transforms the reactive polycrytalline material into a chemically inert system.