Synthesis and characterization of carbon incorporated Fe-N/carbons for methanol-tolerant oxygen reduction reaction of polymer electrolyte fuel cells

A simple method has been developed for synthesis of carbons incorporating FeNx electrocatalysts (FeNC/C-z) based on heat treatment of nitrogen-rich species (pentaethylenehexamine) and iron precursors (FeCl3) on carbon blacks (Vulcan XC-72) under high temperature in a nitrogen atmosphere. These resulting catalysts have been fully characterized by various spectroscopic and analytical techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). Results obtained from the polarization curves show that FeNC/C-3.1 possesses the surpassing electrocatalytic activity and the tolerance to methanol crossover during the oxygen reduction reaction (ORR) among all the FeNC/C-z catalysts, which may be due to their higher surface Fe/C and N/C atomic ratios as well as a dominant carbon incorporated FeNx (x ≈ 4), as revealed from XPS and XAS spectroscopies.