Pt/carbon and Pt/activated carbon catalysts were prepared using a simple chemical reduction method with a view to application in proton exchange membrane (PEM) fuel cells. The catalysts were characterized by X-ray diffraction, energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy, and Brunauer-Emmett-Teller (BET) surface area measurements. The electrochemical performance of the Pt/carbon and Pt/activated carbon catalysts were evaluated by cyclic voltammetry, and linear scan voltammetry testing. Electrochemical measurements indicate that the Pt nanocatalysts exhibited enhanced electrochemically active surface areas and improved activity in the oxygen reduction reaction (ORR) on the activated carbon compared to the pristine carbon. It is suggested that acid activated carbon would provide better catalyst support than pristine carbon in proton exchange membrane fuel cells.