Oxygen Reduction Reaction Activity and Durability of Pt Catalysts Supported on Titanium Carbide

We have prepared Pt nanoparticles supported on titanium carbide (TiC) (Pt/TiC) as an alternative cathode catalyst with high durability at high potentials for polymer electrolyte fuel cells. The Pt/TiC catalysts with and without heat treatment were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Hemispherical Pt nanocrystals were found to be dispersed uniformly on the TiC support after heat treatment at 600 degrees C in 1% H-2/N-2 (Pt/TiC-600 degrees C). The electrochemical properties (cyclic voltammetry, electrochemically active area (ECA), and oxygen reduction reaction (ORR) activity) of Pt/TiC-600 degrees C and a commercial Pt/carbon black (c-Pt/CB) were evaluated by the rotating disk electrode (RDE) technique in 0.1 M HClO4 solution at 25 degrees C. It was found that the kinetically controlled mass activity for the ORR on Pt/TiC-600 degrees C at 0.85 V (507 A g(-1)) was comparable to that of c-Pt/CB (527 A g(-1)). Moreover, the durability of Pt/TiC-600 degrees C examined by a standard potential step protocol (E = 0.9 V1.3 V vs. RHE, holding 30 s at each E) was much higher than that for c-Pt/CB.