Nitrogen and fluorine co-doped graphite nanofibers (N/F–GNF) and their cumulative effect with Fe and Co have been developed as an alternative non-precious metal catalyst for efficient oxygen reduction reaction (ORR) in acidic media. The synergistic effect between the doped hetero atoms and the co-ordinated Fe and Co towards ORR activity and durability of the catalyst is deeply investigated. A high ORR onset potential comparable with commercial Pt/C catalyst is observed with the Fe–Co/NF–GNF catalyst, which indicates that this catalyst is a potential alternative to Pt/C. A fivefold increase in mass activity is achieved by the Fe–Co/NF–GNF catalyst compared to the simple N/F–GNF catalyst, which endorses the significant role of transition metal atoms in enhancing ORR activity. The advanced Fe–Co/NF–GNF catalyst also exhibits complete tolerance to CH₃OH and CO. The Fe–Co/NF–GNF catalyst also exhibits excellent durability towards the ORR with only a 10 mV negative shift in its half wave potential after a 10 000 repeated potential cycling test, whereas in the case of a commercial Pt/C catalyst there was an ∼110 mV negative shift under similar environmental conditions. More stringent corrosive test cycles were also performed by maintaining the cell as high as 1.4 V with a later decrease to 0.6 V vs. RHE for 300 cycles, which showed the excellent durability of the Fe–Co/NF–GNF catalyst in comparison with the Pt/C catalyst. XPS analysis of the Fe–Co/NF–GNF catalyst presents the ORR active chemical states of N (pyridinic-N and graphitic-N) and F (semi-ionic-F) and the co-ordinated sites of Fe and Co species with the dopants. The excellent performance and durability of the Fe–Co/NF–GNF catalyst is due to the synergistic effect between the hetero atoms dopants (N and F) and strong co-ordinating bonds of M–N–C, which protect the graphene layers around the metallic species and greatly mitigates the leaching of Co and Fe during the long term cycling test. The high activity and long term durability of the Fe–Co/NF–GNF catalyst make it a promising ORR electrocatalyst for the fuel cell cathode reaction.

Toward development of alternative metal-free oxygen reduction reaction catalyst, engineering heteroatoms and tuning defects, pore geometry in porous carbon is explored in this study. Simultaneous co-doping of nitrogen and fluorine heteroatoms to porous carbon matrix derived from spent coffee grounds is synthesized and studied for their structural and electrochemical properties. Microscopic analysis of N-F co-doped coffee carbon (N-F/CC) undergoes morphological evolution in its textural properties includes geometrical surface area, pore structure and defects associated with them, features responsible for creating active sites toward ORR activity. N-F/CC catalyst exhibits excellent ORR catalytic activity, methanol and carbon monoxide tolerance in both acidic and alkaline media which makes it highly potential as metal-free oxygen reduction reaction catalyst for polymer electrolyte fuel cell. The developed catalyst is subjected to 10,000 repeated potential cycles in both media and is stable with no degradation in ORR activity. XPS analysis of N-F/CC catalyst revealed the presence of N in the forms of pyridinic-N, pyrrolic-N, graphitic-N, active species and F in the forms of C-F ionic and C-F semi-ionic active forms. Co-existence of all these active species induces the maximum C-C bond polarization, charge re-distribution and high spin densities in the carbon matrices and synergistically ORR activity.