Nafion functionalized carbon nanohorns as catalyst support for proton exchange membrane fuel cells

- Synthesized PFSA functionalized CNHs supported platinum based catalyst.
- Uniform dispersion of platinum is observed for 6 h deposition time.
- PEMFC electrodes are fabricated via multistage PFSA ionomer loading.
- Hydrogen pumping studies confirm low electrode impedance.

Carbon nanohorns (CNHs) are synthesized by DC arc-discharge method in helium atmosphere. The synthesized CNHs are heat treated and then functionalized with Nafion. Platinum is reduced onto Nafion functionalized CNHs through ethylene glycol reduction method. Pt/Nafion-CNHs catalysts are prepared by varying deposition times from 1 to 7 h. Detailed characterization of CNHs and the catalyst is performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). Membrane electrode assemblies are prepared by decal method and electrode performance is analyzed using hydrogen pumping technique. SEM and TGA analysis of soot indicates relatively high level purity of CNHs. TEM and XRD analysis of catalyst with 6 h deposition time reveals that Pt nanoparticles are uniformly deposited on multiwall CNHs surface with particle size of 3-4 nm. Hydrogen pumping studies reveals that Nafion functionalized CNHs act as good catalyst support without hindering electron transfer at electrodes. Hence, these graphitic carbon supports have potential application for high power density applications.

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