Transient Studies of Direct N₂O Decomposition over Pt–Rh Gauze Catalyst. Mechanistic and Kinetic Aspects of Oxygen Formation

Abstract

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 N₂ ¹⁶O over ¹⁸O-pretreated gauze catalyst at temperatures typical of industrial ammonia burners (1073–1273 K). The transient responses of N₂O and the products of its decomposition (O₂ and N₂) 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.