This work investigates the catalytic performance of an industrial steam reforming Ni/SiO2 center dot MgO catalyst toward dry reforming of CH4 under periodic operation. The effects of cracking/regeneration temperatures and O-2 addition during regeneration on the catalyst stability and activity were determined and various characterizations i.e. BET, SEM, XRD, and TPO were employed to relate the catalyst performance with its physical properties. It was found that, without O-2 addition, the catalyst showed good stability at 650 degrees C but observed high deactivation at 750 degrees C due to the formation of encapsulating carbon. The addition of O-2 along with CO2 can eliminate all deactivation at 750 degrees C and no significant loss of catalyst activity was observed for at least 12 cracking/regeneration cycles. The optimal performance for periodic operation was found at the condition with 5 min of the cracking step followed by 5 min of the regeneration step at 750 degrees C with CO2/O-2 ratio of 7/3. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.