Cathodic performance and high potential durability of Ta-SnO2 − δ-supported Pt catalysts for PEFC cathodes

• We synthesized the Ta-doped SnO2 − δ support for the cathode catalysts of PEFCs.
• Electrical conductivity of Ta-SnO2 − δ was 40 times higher than that of Nb-SnO2 − δ.
• The ORR activity of Pt/Ta-SnO2 − δ was higher than that of commercial Pt/carbon.
• The Pt/Ta-SnO2 − δ showed high durability in high potential range (0.9–1.3 V).

We evaluated the cathodic activity and durability of Pt/Ta-SnO2 − δ catalysts for the cathodes of polymer electrolyte fuel cells (PEFCs). The Ta-SnO2 − δ support had a unique fused aggregated structure, for which the electrical conductivity was ca. 40 times higher than that of another candidate high-durability support, Nb-SnO2 − δ with the same support structure. The kinetically controlled current density value at 0.85 V for Pt/Ta-SnO2 − δ reached 0.97 mA cm− 2, which was higher than that for a commercial Pt/CB. Chemical stability of Pt/Ta-SnO2 − δ in the high potential range (0.9–1.3 V) was the same as that of the high-durability Pt/Nb-SnO2 − δ catalyst and was superior to that of commercial Pt/CB and Pt/GCB. We demonstrated that the more highly electrically conductive Pt/Ta-SnO2 − δ is an attractive catalyst for the construction of low-resistance catalyst layers of membrane-electrode assemblies with decreased overpotentials. Thus, we conclude that the Pt/Ta-doped SnO2 − δ catalyst is a superior cathode candidate catalyst for PEFCs.

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