Enhancing electrochemical performance and power generation of air–cathode microbial fuel cell by using Fe3O4@C decorated carbon felt anode

The anode as a critical component of microbial fuel cells (MFCs) directly influences microbial colonization and electron transfer efficiency. In this study, an iron-carbon composite material was synthesized through a one-step pyrolysis method using maltose as the carbon source. Phase analysis confirmed that the material with a composite consisting of Fe 3 O 4 embedded in a carbon matrix (Fe 3 O 4 @CM) was successfully synthesized. Electrochemical characterizations revealed that the electrode modified with Fe 3 O 4 @CM exhibited an electrochemical active area of 65.93 cm 2 and a specific capacitance of 299.4 mF cm −2 , both of which surpassed those modified with Fe 2 O 3 , Fe 3 O 4 and CM. Air–cathode (AC) MFCs were constructed using carbon felt (CF) with different modification materials as the anodes. The influence of various anodes on AC-MFC performance was systematically evaluated through cyclic voltammetry, electrochemical impedance spectroscopy, polarization curves, charge–discharge experiments, and chemical oxygen demand tests. Polarization curve measurements demonstrated that the maximum power density of the AC-MFC with Fe 3 O 4 @CM/CF anode was 861.1 mW m −2 , representing a 2.16-fold enhancement over the AC-MFC with unmodified CF (398.5 mW·m −2 ). Under identical conditions, the Fe 3 O 4 @CM/CF anode exhibited the highest output voltage, the largest electrochemical active area, the lowest internal resistance, and the highest coulombic efficiency, collectively contributing to enhanced power generation. Graphical abstract