The formation, stability and reactivity of surface isocyanate species with CO, NO, and O-2 has been examined over Rh/TiO2(W6+) catalysts, under conditions of NO reduction by CO, using FTIR and transient MS techniques. It has been found that W6+ doping of TiO2 results in stabilization of the Rh-NCO species and in expansion of the temperature window of N2O formation toward lower temperatures by ca. 50 degrees C. Surface isocyanates react with NO to yield gasphase N2O, thus providing an alternative route for the production of nitrous oxide.