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

• Published in: Energy & fuels 2022-02, Vol.36 (4), p.2108-2122
• Main Authors: Das, Sumanta Kumar, Kesh, Aiswarya, Akula, Srinu, Sahu, Akhila Kumar
• Format: Article
• Language: English
• Subjects: Fuel Cells
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/acs.energyfuels.1c03174

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.