Porphyrin-enhanced microbial fuel cell with PCN-600 electrocatalyst for efficient oxygen reduction reaction and eco-friendly energy generation

Microbial fuel cells (MFCs) stand as a sustainable alternative for wastewater treatment and the production of clean energy. The effectiveness of this technology is intricately linked to the cathodic oxygen reduction reaction (ORR). The exceptional tunability of metal–organic frameworks (MOFs) offers a distinctive platform for customizing their inherent properties, making them promising candidates as new electrocatalysts. In this study, metalloporphyrin MOF (PCN-600) with 1D channels and micro/mesoporous structure was prepared utilizing the preassembled [Fe₃O(OOCCH₃)₆] building blocks. Electrochemical measurements demonstrated the superior ORR performance of PCN-600 compared to bare graphite electrodes, with higher onset and half-wave potentials and enhanced electron transfer rates. PCN-600 exhibited a remarkable 52.72 % improvement in power density (179.43 mW m⁻²) compared to the control group (MFC-Ctrl, 88.41 mW m⁻²). Additionally, the chemical oxygen demand (COD) removal efficiency was enhanced, with MFC-PCN-600 achieving 82.58 % COD removal compared to 59.87 % in MFC-Ctrl. The electron-withdrawing N and M−N structure of PCN-600 guarantees an outperforming ORR catalyst toward bioelectricity generation during MFCs performance.