An investigation of carbon supported Pt/C catalysts was carried out with the aim to evaluate their stability under high temperature PEM operation. Nanosized platinum particles supported on carbon were prepared by using a low temperature colloidal route allowing to achieve a mean particle size between 1.5 and 2.3 nm. A pre-evaluation of the various catalysts was carried out in a gas-fed sulfuric acid electrolyte half cell. The catalysts that showed the most proper compromise in terms of activity and stability under accelerated corrosion conditions were selected for further analysis under PEM configuration at 130 {degree sign}C. Electrochemical active surface area and catalyst performance were measured at 80 {degree sign}C before and after operation at 130 {degree sign}C. The variation of electrochemical active surface area after high temperature operation was analysed.