A series of thin Pt films were deposited by dc magnetron sputtering directly on a commercial hydrophobic carbon paper substrate having a thin microporous Vulcan-XC72 layer or upon a thin Ti sublayer sputtered on the top of the microporous carbon film. The electrocatalytic properties of the sputtered Pt films toward the oxygen reduction reaction were investigated in 0.5 M H2SO4 solution and in a hydrogen PEM fuel cell. The catalyst with ultralow Pt loading of 22 mu g cm(-2) deposited on a 33 angstrom thick Ti sublayer is robust, mechanically stable, possesses highly developed surface area and improved catalytic efficiency. Its performance as a MEA cathode in a single hydrogen PEM fuel cell (577 mA cm(-2) at 0.4 V cell voltages and a maximum power of 0.954W) proved to be much superior compared to that of MEA with the same cathode Pt loading but without Ti sublayer (173 mA cm(-2) at 0.4 V, 0.231W, respectively). (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.