Carbonaceous thin film coated on nanoparticle as fuel cell catalyst formed by one-pot hybrid physical–chemical vapor deposition of iron phthalocyanine

The development of new methods for the formation of noble-metal-free fuel cell catalysts is currently important in order to provide active catalysts and to realize fuel cell advancements. We attempted the one-pot physical–chemical vapor deposition of iron phthalocyanine (FePc) on the surface of high-surface-area carbon particles as the substrate. This method enabled loading of FePc on the carbon material and concurrent heat treatment, resulting in the formation of carbon–carbon composite nanoparticles with a catalytic activity for the cathodic oxygen reduction, which functioned in a cathode in the polymer electrolyte fuel cell. The increasing temperature rate during the heat treatment, arranging the FePc–substrate configuration and simply adjusting their ratio controlled the amount of the loading and the thickness of the carbonaceous film, which was demonstrated by the transmission electron microscope images and the pore structure analysis. The catalytic activity was dependent on these parameters. The partial retention of the center structure of the FePc (Fe–Nx moiety) in the carbonaceous thin film was indicated by the Fe-K edge extended X-ray absorption fine structure. The results of this study also showed the possibility of coating various kinds of nanoparticles with functional carbonaceous thin films.