In the present study, various commercial carbon black materials like Vulcan XC72, Black Pearl 2000, and Regal 330 were used as supporting material for polymer electrolyte membrane fuel cell (PEMFC) electrocatalysts. A promising carbon material exhibiting hollow core mesoporous shell (HCMS) structure was synthesized by the template replication of the silica spheres with solid core and mesoporous shell structure. Two carbon supports with similar pore texture were prepared by the injection of two different carbon precursors. 20 wt% Pt/C electrocatalysts were synthesized by microwave irradiation method as the cathode electrode for PEMFC. Ex situ characterization of the electrocatalysts was performed by N-2 adsorption analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). Electrochemical characterization of the electrocatalysts was conducted by cyclic voltammetry (CV) analysis. Effect of different carbon supports on the cathode performance was investigated in a single cell H-2/O-2 PEMFC. Fuel cell performance tests and additional ex situ characterizations showed that HCMS carbons exhibit good support characteristics with improved single cell performance. For the cathode electrode kinetics, promising fuel cell performance results were obtained as compared to the commercial carbon blacks. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.