Static magnetic field-enhanced cathodic electrocatalysis of Fe3O4-based nitrogen-doped carbon for improving the performance of microbial fuel cells

Abstract

Enhancing oxygen reduction reaction (ORR) electrocatalysis through an external static magnetic field to improve the performance of microbial fuel cells (MFCs) is technically feasible, but its application in MFCs remains largely unexplored. Herein, we present a Fe₃O₄-based nitrogen-doped carbon (Fe₃O₄@NC2) magnetic catalyst that significantly boosts ORR catalytic activity, increasing the half-wave potential (E_1/2) of the ORR by approximately 20 mV with a magnetic field strength of 140 mT. When the Fe₃O₄@NC2 cathode is combined with an external magnetic field into the MFCs, the maximum power density of the MFC can reach 553.17 ± 7.16 mW m⁻². This performance notably exceeds that of the same MFCs operated without a magnetic field (522.26 ± 4.25 m⁻²) and that of MFCs equipped with a Pt/C cathode (447.29 ± 2.16 mW m⁻²). This study introduces an effective and straightforward cathodic magnetic enhancement approach, offering promising avenues for advancing MFCs technology.