Iron-embedded nitrogen doped carbon frameworks as robust catalyst for oxygen reduction reaction in microbial fuel cells

Abstract

A kind of 3D Fe-embedded N doped carbon framework catalyst is successfully developed and tested in the present work as a robust cathode catalyst for microbial fuel cells (MFCs). Due to the well-arranged mesopores, the high surface area, the interconnected conductive networks as well as the finely dispersed Fe-N active species, the as-prepared 3D Fe-N-C catalyst exhibits significantly enhanced ORR activity compared to commercial Pt/C. More precisely, the 3D Fe-N-C yields a more-positive half-wave potential of −0.08 V (vs. SCE) and remarkably stable limiting current of ∼6.2 mA cm−2. The 3D Fe-N-C shows also an excellent tolerance to methanol as well as remarkably long-term stability with more than 82.4% retention of its initial activity after 55.5 h operation. Based on the as-prepared 3D Fe-N-C as the air cathode catalyst, a stable microbial fuel cell (MFC) device is fabricated and tested, performing a maximum power density of 3118.9 mW m−2 at a high current density of 9980.8 mA m−2. More importantly, it is found that the Fe-N-C MAFC device could steadily operate for more than 250 h in a feed period, which is substantially longer than the Pt/C-MFC device. © 2016