Development of enhanced corrosion resistant carbon supports for Pt/C catalysts for the oxygen electroreduction reaction

A sharp increase in the cathode potential (up to 1.4 V. vs. RHE) due to the simultaneous presence of oxygen (air) and hydrogen in the anode side is the main degradation cause of Pt/C catalysts for polymer electrolyte fuel cells (PEMFC) using as a power source for cars. This potential is much higher than the carbon oxidation potential, so the corrosion resistance of a carbon support is an important parameters of the PEMFC effective operation. In this paper, the stability of commercial carbon supports was improved by modifying the surface under different conditions. A series of the 50 % Pt/C catalysts were synthesized and their stabilities (electrochemical surface area of Pt) were investigated using "start-stop cycling" in an electrochemical cell at 1.0-1.5 vs. RHE potentials with a sweep rate of 0.5 V/s for 60,000 cycles. Commercial 40%Pt/Vulcan XC- 72 and catalysts were selected for a comparison. It is shown that the support carbonization with propane-butane mixture at 750°C increases, while the activation in air with subsequent treatment at 800°C lowers the corrosion resistance of Pt/C catalysts.