Densely accessible single atom Fe sites dispersed on porous carbon as highly stable and active ORR catalyst for PEMFC

Single-atom Fe-N-C catalysts have received ever-growing interest in proton exchange membrane fuel cells (PEMFCs) application for their utmost atomic utilization in oxygen reduction reaction (ORR). However, developing atomically dispersed Fe-N-C catalysts with both satisfactory activity and excellent stability presents great challenges. Herein, a template-activator combined strategy is developed to construct ORR catalysts with densely accessible single-atom Fe sites dispersed on hierarchically porous carbon networks. The optimized catalyst exhibits excellent oxygen reduction activity with a half-wave potential of 0.84 V and surprising stability with 93.6% retention of the initial current density after 24 hours of chronoamperometric test in acidic media. Notably, when assembled in a H2-O2 fuel cell, it shows remarkable long-term durability with only 16% loss in current density during the first 10 hours.