Surface property of the Cu doped γ-Al2O3: A density functional theory study

Cu/gamma-Al2O3 catalysts are widely used in many catalytic processes. Investigation into the catalysts structure at molecular level is the basis for the elucidation of the reaction mechanisms and favors the developments of the catalysts. In the present work, periodic density functional theory calculations were performed to investigate the interface of alumina with copper oxides. The interface model is chosen as the substitution of the surface Al atoms of gamma-Al2O3 with Cu, and H is used as the ion for charge balance. It is found that the substitution of surface Al a by Cu2+ is thermodynamically accessible. Gibbs free energy calculations show that the dehydration temperature for the gamma-Al2O3 (1 1 0) surface after substitution is higher than that of on the original gamma-Al2O3 (1 1 0) and CuAl2O4 surface. The oxygen vacancy formation energies for the (1 0 0)-5Cu-dehy-2w and (1 1 0)-4Cu-dehy-2w are 213 and 367 kJ/mol, respectively. In addition, the Cu doped-gamma-Al2O3 interface could strengthen the binding of Cu with the alumina surface. The results provide molecular level insights for the understanding of the interface structures and physical chemistry properties of alumina with copper oxides.