Known supported catalysts for the Fenton degradation of organic contaminants must be used in acidified solutions, where they leach Fe and consequently lose activity. In this study. FexOy nanoparticles (average diameter = 3 nm) were immobilized onto multiwalled carbon nanotubes using a facile microwave-assisted polyol method to produce a Fenton catalyst that was active at neutral pH. Despite an Fe content of only 1.5 wt%, FexOy-MWNTs catalyzed the near-complete degradation of 50 mg L-1 of an organic dye contaminant in water at pH(0) = 7 in 30 min. At neutral pH, Fe leaching from the catalyst was minimal. Factors affecting the activity and stability of the catalyst were studied and a method was developed to regenerate the catalyst, which could be separated and reused with a small loss in activity. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.