Sulfur‐Doped Porphyrinic Carbon Nanostructures Synthesized with Amorphous MoS 2 for the Oxygen Reduction Reaction in an Acidic Medium

To develop doped carbon nanostructures as non‐precious metal cathode catalysts, nanocomposites were synthesized by using SBA‐15 and 5,10,15,20‐tetrakis(4‐methoxyphenyl)porphyrin–iron(III) chloride with different ratios of amorphous MoS 2 precursor. From various analyses, it was found that, during pyrolysis at 900 °C under an N 2 atmosphere, the amorphous MoS 2 precursor decomposed into Mo and S, facilitating the formation of graphene sheet‐like carbon with MoC and doping of sulfur in the carbon. In the nanocomposite formed from 10 wt % MoS 2 precursor (denoted as Mo/S/PC‐10), most of the MoS 2 was decomposed, thus forming S‐doped carbon, which was grown on the MoC phase without crystalline MoS 2 . Furthermore, Mo/S/PC‐10 exhibited better performance in the oxygen reduction reaction (specific activity of 1.23 mA cm −2 at 0.9 V and half‐wave potential of 0.864 V) than a commercial Pt catalyst, owing to a heteroatom‐doped carbon nanostructure with a fairly high specific surface area. In the polarization curve of the unit‐cell performance measured at 80 °C under ambient pressure, Mo/S/PC‐10 as a cathode catalyst exhibited an optimal power density of 314 mW cm −2 and a current density of 280 mA cm −2 at 0.6 V.