Microorganisms were observed to facilitate cathodic oxygen reduction and enhance cathode performance of microbial fuel cells (MFCs). However, the long-term activity and stability of bio-catalyzed cathode needs to be explored. This study evaluated the long-term performance of bio-catalyzed cathode and iron(II) phthalocyanine (FePc)-catalyzed cathode MFCs through effluent water quality, electricity production and electrochemical impedance spectroscopy (EIS) analysis under different scenarios, including conventional wastewater treatment and energy harvesting using a power management system (PMS). During the continuous operation, both systems demonstrated high chemical oxygen demand and ammonium removal, but bio-catalyzed cathode MFCs could achieve significantly better total nitrogen removal than FePc-catalyzed cathode MFCs. The FePc-coated cathode showed constant cathode potential during the entire operation period, but the biocathode showed varied but step-wise increased cathode potential to achieve more than 500 mV versus the standard hydrogen electrode, likely due to the gradual enrichment of biocathode biofilm. EIS analysis revealed that biocathode had higher ohmic resistance than bare carbon felt cathode but the microbial biofilm could largely decrease polarization resistance of cathode material. Microbial community analysis has shown the presence of nitrifying and denitrifying bacteria in the bio-catalyzed cathode biofilm. When connecting PMS, both bio-catalyzed cathode and FePc-catalyzed cathode MFCs successfully charged a capacitor, but the bio-catalyzed cathode MFC voltage significantly dropped to less than 100 mV after charging for 91 h, and gradually recovered when disconnecting PMS. This study has demonstrated the potential application of oxygen reduction bio-catalyzed cathode MFCs for continuous wastewater treatment and energy harvesting for long period of time.

观察到微生物可促进阴极氧的还原并增强微生物燃料电池（MFCs）的阴极性能。然而，需要探索生物催化阴极的长期活性和稳定性。这项研究通过废水的水质，发电量和电化学阻抗谱（EIS）分析在不同情况下（包括常规废水处理和废水处理）对生物催化阴极和酞菁铁（II）催化阴极MFC的长期性能进行了评估。使用电源管理系统（PMS）收集能量。在连续运行过程中，两个系统均显示出较高的化学需氧量和铵去除率，但生物催化阴极MFC的总氮去除率明显高于FePc催化阴极MFC。涂有FePc的阴极在整个操作期间均显示恒定的阴极电势，但生物阴极显示出变化但逐步增加的阴极电势，与标准氢电极相比可达到500 mV以上，这可能是由于生物阴极生物膜的逐渐富集。EIS分析表明，生物阴极比裸碳毡阴极具有更高的欧姆电阻，但微生物膜可以大大降低阴极材料的极化电阻。微生物群落分析表明，生物催化的阴极生物膜中存在硝化细菌和反硝化细菌。连接PMS时，生物催化的阴极MFC和FePc催化的阴极MFC均成功为电容器充电，但充电91 h后，生物催化的阴极MFC电压显着下降至小于100 mV，并在断开PMS时逐渐恢复。这项研究证明了氧还原生物催化阴极MFCs在长时间连续废水处理和能量收集中的潜在应用。