Enhanced extracellular electron transfer of CoMn₂O₄@CNT as microbial fuel cell anode

Microbial fuel cells (MFCs) can recover electrical energy from organic wastewater using electrically active microorganisms (EAMs), both for wastewater treatment and electricity generation. However, the relatively low power output density currently prevents MFCs from being used commercially. The main reasons are low microbial load and slow extracellular electron transfer (EET) at the anode interface. Increasing the load of EAMs on the anode and the efficiency of EET are considered to be effective strategies to improve the overall performance of MFCs. Compared to the primitive carbon cloth (CC) anode, the CoMn₂O₄@CNT complex anode has a multi-layer porous network structure that provides a rich biocompatibility site for bacterial attachment. In addition, CoMn₂O₄@CNT can release positively charged cobalt ions (Co²⁺/Co³⁺) and manganese ions (Mn²⁺/Mn³⁺/Mn⁴⁺). Bimetallic cooperative regulation can effectively promote the attachment of electronegative microorganisms and the EET rate. In this study, CoMn₂O₄@CNT anode MFC exhibited excellent electrochemical performance (R_ct 15.14 Ω) and electrical production (3269.34 mW m⁻² 0.62 V), and the output power density was 4.1 times that of CC anode MFC.