Performance enhancement of microbial fuel cells through g-C₃N₄-embedded biochar anodes

Global demand for sustainable energy technologies capable of simultaneously generating electricity and treating wastewater has intensified interest in microbial fuel cells (MFCs). However, their practical application remains limited by low power density and insufficient electron‐transfer efficiency at the anode. This study addresses this challenge by embedding graphitic carbon nitride (g-C₃N₄), a metal-free and environmentally benign material, into rice-husk-derived biochar to develop a low-cost, sustainable anode. Unlike conventional surface-coated electrodes, the embedded configuration enhances internal electron-transfer pathways and promotes microbial colonization throughout the electrode matrix. Anodes with 5, 10, and 12 wt% g-C₃N₄ were evaluated to clarify how nitrogen-rich functional groups and carbon conductivity interact to influence MFC performance. The 5 wt% anode exhibited the most favorable electrochemical behavior, achieving a maximum power density of 43.245 μW/cm²—approximately 1.9 times higher than the unmodified anode—highlighting the effectiveness of moderate nitrogen incorporation. Excessive loading reduced performance due to impaired conductivity. These findings provide new insight into the design of sustainable, biomass-derived anode materials and demonstrate the potential of g-C₃N₄-embedded biochar for scalable, environmentally friendly MFC applications. This work contributes to the global scientific effort toward low-cost, renewable energy systems for wastewater treatment and decentralized power generation.