Abstract
Microbial fuel cells (MFCs) play significant role in solving energy crisis and water pollution, while their scale-up is restricted by the sluggish oxygen reduction reaction (ORR) on the cathode. Herein, the influence of different metal and nitrogen co-doped porous carbon (Fe-NpC, Mn-NpC and Ni-NpC) on the ORR reactivity are investigated, which is obtained in the following order: Fe-NpC > Mn-NpC > Ni-NpC. The X-ray absorption spectroscopy verifies the Fe-NpC catalyst having atomically dispersed Fe–N4 moieties. The Fe-NpC catalyst exhibits an ultrahigh specific surface area of 2099 m2 g−1 and splendid ORR performance with a rather positive half wave potential of 0.902 V in alkaline and 0.705 V (vs. Reversible Hydrogen Electrode) in neutral electrolytes. The excellent ORR characteristic provides sufficient feasibility for Fe-NpC as cathode catalyst to construct MFC. The Fe-NpC-MFC performs the highest power density of 1793 ± 77 mW m−2, open circuit voltage of 775 mV, favorable output stability of 6.0% decline in 430 h, and chemical oxygen demand removal of 90.3 ± 4.3%, all surpassing the benchmark Pt/C-MFC. This study demonstrates that the combination of the longevity of Fe-NpC catalyst with its atomically dispersed Fe–N4 structure can ensure a stable and long-term application in MFCs treating wastewater.
Published Version
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