A density functional study of water and methanol chemisorption on MgO(1Â 1Â 0)

Periodic density functional calculations have been used to study the adsorption of water and methanol on the (1 1 0) surface of MgO. A brief re-investigation of the (1 0 0) surface confirms previous results that the dissociative adsorption of H2O on MgO(1 0 0) is energetically unfavourable. We find the same to be true of CH3OH. On the (1 1 0) surface, both water and methanol are strongly adsorbed, with high energies of adsorption. Water is dissociatively adsorbed with ΔE ranging from −290 kJ/mol at low coverage to −240 kJ/mol at a full monolayer. The adsorption of water is found not to be activated. ΔE for adsorption of methanol ranges from −255 to −240 kJ/mol. A mixed water-methanol adsorption layer is also possible, with a similar binding energy.