Performance of a Fe-N-C Catalyst in Single-chamber MFC Air-cathode at Neutral Media

Microbial fuel cells (MFC) are technologies that use microorganisms that transfer electrons to the anode, which flows to the cathode to find a final electron acceptor. Oxygen (O2) is the most widely used electron acceptor as it can diffuse through air-cathodes in single-chamber MFCs. However, microorganisms need neutral to slightly acid pH to survive, which is detrimental to the oxygen reduction reaction (ORR). Therefore, catalysts are needed at the air-cathodes to sustain a stable operation of single-chamber MFCs. Here, we report that the use of small amount (0.15 mg cm−2) of a Fe-N-C catalyst with carbon black in air-cathodes promote the ORR in neutral media and can sustain a stable MFC operation, keeping cell voltages of 0.3 V for 8 days.