Methane cracking has the potential to produce high purity, carbon monoxide-free hydrogen suitable for application in PEM fuel cells. The 2 products of the reaction are molecular hydrogen and solid carbon. The carbon appears in the form of carbon. laments whose growth is hindered by carbon encapsulation leading to total deactivation of the catalyst. Several attempts have been made to regenerate the catalyst, mainly by gasifying the carbon. lament in air or steam. Our work on 5-wt% Ni/gamma Al2O3 indicated that after complete gasification of the carbon the catalyst lost nearly all its activity toward methane cracking. However, if the gasification proceeds to only a certain extent, it is possible to recover significant activity the catalyst. This technique, also known as partial regeneration, is a promising strategy to overcome the challenge of catalyst deactivation in catalytic decomposition of methane. Optimization of the partial regeneration method is presented here, in particular the extent to which the gasification should take place. Activity of the catalyst and the extent of gasification have been monitored through thermogravimetric analysis.