ORR activity and direct ethanol fuel cell performance of carbon-supported Pt-M (M ) Fe, Co, and Cr) alloys prepared by polyol reduction method

A polyol reduction method is employed to prepare carbon-supported Pt and Pt-M (M ) Fe, Co, and Cr) alloy catalysts by simultaneous reduction and decomposition of metal precursors with 1,2-hexadecanediol in the presence of nonanoic acid and nonylamine protecting agents. The prepared materials are characterized by powder XRD, HRTEM, and EDX. The face-centered cubic structure of Pt in the prepared materials is evident from XRD. Good dispersion of Pt and Pt alloy nanoparticles on the carbon support is seen from the highresolution TEM images. The presence of respective elements with controlled composition is observed from EDX analysis. Electrochemical performance of the prepared materials is investigated by cyclic voltammetry and tested in a single-cell DEFC. The inhibition of formation of (hydr)oxy species on the Pt surface by the presence of alloying elements is observed. Oxygen reduction activity of the Pt-M/C (M ) Fe, Co, and Cr) is found to be ̃1.5 times higher than that of the as-synthesized and commercial Pt/C catalysts. Single-cell DEFC tests indicated the good performance of Pt-M/C (M ) Fe, Co, and Cr) compared with that of the as-synthesized and commercial Pt/C catalysts. The DEFC performance increased in the order Pt/Ccomm < Pt/Cas-syn < Pt-Fe/C < Pt-Co/C ̃ Pt-Cr/C. Stability under DEFC operating conditions for 50 h indicated the good stability of Pt alloys compared with that of Pt catalysts. © 2009 American Chemical Society.