Stability of Corrosion-Resistant Magnéli-Phase Ti[sub 4]O[sub 7]-Supported PEMFC Catalysts at High Potentials

Abstract

Substoichiometric titanium oxide (Ti4 O7) -supported Pt catalysts were prepared and their electrochemical properties, particularly the effects of high-potential conditions on the activity and stability of Pt Ti4 O7 catalysts, were compared to those of PtC catalyst. Polarization measurements using membrane electrode assemblies revealed that the Pt Ti4 O7 cathode shows a similar activity for the oxygen reduction reaction as PtC catalyst at 80?C. A high-potential holding test (1 h holding at 1.0-1.5 V vs anode) demonstrated that the Pt Ti4 O7 catalyst is quite stable against high potential up to 1.5 V. A single cell using a Pt Ti4 O7 cathode was operated at 80?C, and voltage stability for >350 h with H2 O2 was also demonstrated. ? 2008 The Electrochemical Society.