Polypyrrole‐Modified‐Carbon‐Supported Ru‐Pt Nanoparticles as Highly Methanol‐Tolerant Electrocatalysts for the Oxygen‐Reduction Reaction

The modification of mesoporous carbon black with polypyrrole (C‐PP) facilitates the incorporation of homogeneously dispersed nanosized Ru‐Pt particles (1–2 nm) onto the support. Polypyrrole‐modified carbon supports were prepared by the addition of different amounts of pyrrole, followed by in situ polymerization through oxidative treatments. The Ru‐Pt/C‐PP electrocatalysts were tested in the oxygen‐reduction reaction in methanol‐containing acidic electrolytes by using both conventional electrochemical techniques and in a direct methanol single cell. The performance of Ru‐Pt/C‐PP was far superior to that of Pt/C for the oxygen‐reduction reaction in the direct methanol fuel cell. Under severe methanol‐crossover conditions, the maximum power density that was delivered by Ru‐Pt/C‐PP after degradation tests was decreased by 20 %, whereas that of Pt/C decreased by 75 %. Thus, the presence of Ru oxides in the cathode led to more tolerant electrocatalysts towards the presence of methanol in the reaction medium during the oxygen‐reduction reaction.