A density functional study of CO₂ adsorption on the (100) face of Cu(9,4,1) cluster model

The adsorption modes of inert CO₂ on the (100) face of Cu(9,4,1) cluster model have been studies by the Slater DFT code of the Amsterdam density functional (ADF) program. The side-on adsorption mode with near linear CO₂ lying at the short bridge site has the highest binding energy of 26.31 kJ mol^-1. The binding energies of CO₂ in similar geometry on the cross bridge, hollow, and on-top sites vary from 19.66 to 21.8 kJ mol^-1. The investigation also revealed that a number of CO₂ bent modes with O-C-O angles equal to ≈ 150° can coordinate with the surface with binding energies ranging from 9.66 to 23.56 kJ mol^-1. Further calculations indicated that to cause the CO₂ molecule to bend to ≈ 150°, there is negative charge transferred from the copper cluster to the CO₂ molecule.