The NO reduction characteristics of a vanadium supported activated carbon catalyst have been examined without addition of reducing agent (i.e., ammonia, NH3). The catalyst was prepared from commercial coconut activated carbon that was impregnated with 2.8 wt.% vanadium. The NO reduction reactions were conducted under conditions with 3% O-2 and without O-2 in a fixed bed reactor. In the condition with 02, 84% NO conversion resulted at 360 degrees C, though the catalyst began to burnout at a temperature higher than 300 degrees C and with large quantities of CO and CO2 being emitted. In the condition without O-2, the burnout of the catalyst was insignificant and resulted in small amounts of CO and CO2. The NO conversion increased gradually with the reaction temperature reaching 78% at 450 degrees C. SEM photographs and BET measurements are useful tools for understanding the burnout phenomena with the catalyst. The burnout in the condition with 02 resulted in the catalyst rapidly losing its activity. However, in the condition without 02, the catalyst gradually lost its activity and finally approached a steady state. Moreover, the modified mechanism scheme of the NO reduction reactions without NH3 and with the catalyst is described and the global rate equation for the reaction without 02 is obtained. (c) 2007 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.