Accidents at TMI, USA and the recent one at Fukushima, JAPAN has emphasized the need for mitigation of hydrogen generated in nuclear reactor containment during accidental conditions. Passive Autocatalytic Recombiner (PAR) is one of the best solutions to deal with such situations during loss of coolant accidents. A novel breed of catalysts based on cordierite supported Pt nanoparticles has been prepared by chemical reduction route for mitigating the hydrogen generated during such accidents. These catalysts have been characterized for their phase purity, surface composition, surface area, particle size, morphology and elemental loading of the noble metal. The supported noble metal particles are found to be of 7 nm-11 nm dimensions, depending on the extent of noble metal loading. The catalytic activity of these catalysts has been evaluated in presence and absence of various prospective contaminants like carbon monoxide, carbon dioxide, methane, humidity, and condensed water in a laboratory scale reactor. Developed catalysts have been found to be catalytically active for H-2-O-2 recombination reaction in presence of 100% relative humidity and 2000 ppm of carbon monoxide. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.