For elucidating the mechanistic aspects of oxygen formation during N2O decomposition over commercial woven Pt-Rh gauze, transient experiments were carried out in the temporal analysis of products (TAP) reactor by pulsing N-2 O-16 over O-18-pretreated gauze catalyst at temperatures typical of industrial ammonia burners (1073 - 1273 K). The transient responses of N2O and the products of its decomposition (O-2 and N-2) were fitted to two different mechanistic models. From the isotopic studies and the fitting of transient experiments, two separate routes of oxygen formation during catalytic N2O decomposition have been identified. Oxygen is produced via both (i) interaction of N2O with adsorbed oxygen species formed from N2O and ( ii) recombination of adsorbed oxygen species on the catalyst surface. The relative contribution of these reaction pathways depends on the reaction temperature.