Oxygen reduction on composite FeOx nanoparticles embedded in porous carbon

Composite FeOx nanoparticles embedded in carbon were prepared by the chemical vapor deposition of CH4 on iron phthalocyanine. They showed relatively high catalytic activity towards oxygen reduction, demonstrating their potential applicability as inexpensive platinum-free cathode catalysts for use in low-temperature fuel cells. Fe oxides and Fe metal embedded in porous carbon, not nitrogen-coordinated iron compounds, were shown to be the active catalytic sites in composite FeOx nanoparticles embedded in carbon.

► FeOx embedded in carbon (FeEC) was prepared as a platinum-free cathode catalyst.
► Fe oxides and Fe metal were the main active catalytic sites in FeEC.
► The higher ORR activity of FeEC was from the higher electronic density of states near Fermi level.
► The improved stability of FeEC stemmed from the carbon layers covering the composite particles.