Nitrogen-doped carbon (CNx) nanotubes were synthesized by thermal decomposition of ferrocene/ethylenediamine mixture at 600-900°C. The effect of the temperature on the growth and structure of CNx nanotubes was studied by transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. With increasing growth temperature, the total nitrogen content of CNx nanotubes was decreased from 8.93 to 6.01 at.%. The N configurations were changed from pyrrolic-N to quaternary-N when increasing the temperature. Examination of the catalytic activities of the nanotubes for oxygen reduction reaction by rotating disk electrode measurements and single-cell tests shows that the onset potential for oxygen reduction in 0.5 M H 2 SO 4 of the most effective catalyst (CNx nanotubes synthesized at 900°C) was 0.83 V versus the normal hydrogen electrode. A current density of 0.07 A cm -2 at 0.6 V was obtained in an H 2 /O 2 proton-exchange membrane fuel cell at a cathode catalyst loading of 2 mg cm -2 .

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A platinum nanoparticle-reduced graphene oxide (Pt-RGO) nanohybrid for proton exchange membrane fuel cell (PEMFC) application was successfully prepared. The Pt nanoparticles (Pt NPs) were deposited onto chemically converted graphene nanosheets via ethylene glycol (EG) reduction. According to the powder X-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) analysis, the face-centered cubic Pt NPs (3-5 nm in diameter) were homogeneously dispersed on the RGO nanosheets. The electrochemically active surface area and PEMFC power density of the Pt-RGO nanohybrid were determined to be 33.26 m2/g and 480 mW/cm2 (maximum values), respectively, at 75 degrees C and at a relative humidity (RH) of 100% in a single-cell test experiment.

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