The oxygen adsorption on Ag/LSM(0 01) catalysts surfaces has been investigated using first-principles density functional theory calculations. The most favorable oxygen adsorption sites are found to be atop surface Mn atoms on the MnO2-terminated surface and on the hollow positions of the La(Sr)O-terminated LSM(0 01) surface. The calculated adsorption energies for Ag atom demonstrate that the Ag adsorption at O site is much more favorable than Mn site. The atomic relaxation results indicate that Ag doping produces a strong local perturbation and a large effect on the surface properties. No significant improvement for oxygen adsorption is found due to Ag doping. However, the O-2 adsorption energy increases from 0.495 eV to 0.937 eV due to the pre-adsorbed Ag. It is pre-adsorbed Ag that facilitates O-2 adsorption on surface. The bond length and bond population of O-2 molecule indicate that Ag atom facilitates O-2 molecule dissociative adsorption. The adsorbed Ag on LSM strengthens its activity as SOFCs cathode by acting as an active center at the surface. (C) 2012 Elsevier B.V. All rights reserved.