Pt nanoparticles supported on carbon monofluoride (CFx), synthesized from H2PtCl6 using NaHB4 as a reducing agent has been investigated as a cathode electrocatalyst in fuel cells. Surface characterization, performed by transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD), shows a homogeneous distribution and high dispersion of metal particles. Kinetic parameters for the electrocatalyst are also obtained from the steady state measurements using a rotating disk electrode (RDE) in 0.5 M H2SO4 solution. Analysis by Koutecky-Levich equation indicates an overall 4 e(-) oxygen reduction reaction (ORR). Evaluation of the catalyst in single cell membrane electrode assemblies (MEAs) for proton exchange membrane based Direct Methanol Fuel Cell (DMFC) and H-2 Fuel Cell at different temperatures and flows of O-2 and Air are shown and compared against commercial Pt/C as the cathode electrocatalyst. Evaluation of Pt/CFx in H-2 fed fuel cells shows a comparable performance against a commercial catalyst having a higher platinum loading. However, in direct methanol fuel cell cathodes, an improved performance is observed at low O-2 and air flows showing up to 60-70% increase in the peak power density at very low flows (60 mL min(-1)). (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.