N-, F-, and Fe-Doped Mesoporous Carbon Derived from Corncob Waste and Creating Oxygen Reduction Reaction Active Centers with a Maximum Charge Density of ≥0.25 for a Polymer Electrolyte Fuel Cell Catalyst

Defect chemistry, increasing charge, and spin density in the carbon lattice are keys to the advancement of any alternative non-precious cathodic oxygen reduction electrocatalyst for broad dissemination of polymer electrolyte fuel cells (PEFCs). In view of this prospective, we developed porous carbon from a biomass-derived source, such as corncob (CC) waste, and heteroatom N and F doping on it to increase functionalities and defects. Fe was further incorporated in N-F/CC-C to enhance the oxygen reduction reaction (ORR) activity and power density in PEFCs. Finely mesoporous carbon derived from CC undergoes structural transformation, having numerous open edge active sites after N-F co-doping, and alters the textural characteristics favorable for ORR. The Fe/N-F/CC-C catalyst shows outstanding ORR activity, insensitivity toward CH3OH in alkaline conditions, and insignificant deprivation in ORR activity after a recurrent 10 000 potential cycles that prevails a highly enticing ORR electrocatalyst for PEFCs. The presence of active pyridinic, pyrrolic, and graphitic kinds of nitrogen along with ionic and semi-ionic active bonds between C and F in graphitic arrangement of the Fe/N-F/CC-C catalyst cumulatively ameliorates the catalytic activity. Furthermore, generation of maximal C-C bond polarization, redistribution in charge density, and high spin densities in the carbon lattice of the catalysts were theoretically investigated, which cumulatively boost the ORR activity.