Reductions of N2O on oxides/hydroxides of nickel, cobalt or manganese supported on carbon fibers were studied. Supports and catalysts were characterized by low temperature argon sorption, temperature-programmed desorption (TPD) of surface oxides and temperature-programmed desorption of ammonia (TPAD), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR). Conversion of N2O depended on the initial pretreatment of the support, the origin of the effect lying in a different distribution of active material. The differences in distribution influenced also the mobility of surface oxygen. The presence of more labile oxygen resulted in its easier transfer and faster formation of CO2. (c) 2005 Elsevier B.V. All rights reserved.