Laser-ablation generated gold-vanadium oxide cluster cations Au2VOx+ (x = 3, 4) were mass-selected by a quadrupole mass filter and interacted with H-2 in an ion trap reactor. The reactions were characterized by mass spectrometry and density functional theory calculations. The Au2VO4+ cluster can oxidize two H-2 molecules consecutively to produce Au2VO3+ and then Au2VO2+, the latter of which can react with one O-2 molecule to regenerate Au2VO4+. Therefore, a catalytic cycle for H-2 oxidation by O-2 mediated with the Au2VO2+ clusters can be proposed. The theoretical studies predict that the gold atoms in both Au2VO4+ and Au2VO3+ are the active adsorption sites and facilitate the heterolytic cleavage of H-2 in collaboration with the separate O-2 ions of the vanadium oxide support. The consecutively oxidative reactivity of Au2VO4+ is attributed to the activation and dissociation of the superoxide or peroxide species (O-2(center dot-) or O-2(2-)) into two reactive atomic oxygen species (O2-) with the promotional effect of gold atoms acting as electron donors. This study provides molecular-level insights into the elementary mechanisms of the H-2 catalytic oxidation on the surface.