Novel Graphitised Carbonaceous Materials for Use as a Highly Corrosion‐Tolerant Catalyst Support in Polymer Electrolyte Fuel Cells

Cathode catalysts for polymer electrolyte fuel cells (PEFCs) are prepared by depositing Pt nanoparticles on carbon nanospheres (CNSs) and graphitised carbon nanospheres (GCNSs), and their corrosion‐tolerance and electrocatalytic activities for the oxygen reduction reaction are evaluated. Transmission electron micrographs show that the deposited Pt nanoparticles are well dispersed on CNSs. In Pt/GCNS, Pt nanoparticles accumulate selectively along the edges of GCNSs' polygonal surfaces. Electrochemical measurements with a rotating‐ring disk electrode in an O₂‐saturated H₂SO₄ solution show that Pt/GCNS and Pt/CNS produce less H₂O₂ during oxygen reduction, compared to that obtained with a Pt catalyst on carbon black (CB). Thermogravimetric analysis reveals that GCNSs show greater combustion‐tolerance than CNSs and CB. Furthermore, GCNSs show excellent electrochemical corrosion‐tolerance in a H₂SO₄ solution. These results indicate that GCNSs are superior for use as carbon supports, and can serve as cathode catalysts in PEFCs even under oxidative conditions.