Metal particles supported on metal oxides (MMO) are promising materials with versatile applications such as catalyst in fuel cell technologies. As one of the transition metal oxides, niobium oxide (NbO) demonstrates a wide interesting properties that make it a potentially applicable in MMO materials. Here, the catalytic activity for the O-2 activation of transition metals (Fe, Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au) supported on the NbO has been studied theoretically using density functional theory (DFT). The activation of O-2 molecule and yielding two separated O atoms is an essential step for the oxygen reduction reaction. Our study demonstrates that the transition metals supported on the NbO can act as driving force for O-2 dissociation. Consistent with the prediction of reactivity descriptors, the maximum catalytic activity toward O-2 activation is related to the Pt-supported on the NbO metal oxide. (C) 2017 Elsevier B.V. All rights reserved.