Microbial fuel cells (MFCs) are innovative devices to extract renewable energy using exoelectrogens from wastewater. The performance of MFCs mainly depends on the electron transfer efficiency between the exoelectrogens and the anode materials. In this work, iron carbide (Fe₃C) nanoparticles encapsulated with graphitic carbon layers embedded into biochar (nano-Fe₃C@C anode) were prepared as a binder-free anode material for MFCs. The encapsulated carbon layers can avoid the direct contact between Fe₃C nanoparticles and the electrolyte, thereby effectively inhibiting the dissolution and over-aggregation of nanoparticles, and over 96% of the in 10–70 nm. Moreover, this configuration enhanced the interfacial contact between the Fe₃C nanoparticles and the biochar matrix, resulting in a significantly lower charge transfer resistance (R_ct) of 39.30 Ω compared to SC and CC anodes. This hybrid structure also promoted biocompatibility and extracellular electron transfer (EET) of exoelectrogens with nano-Fe₃C anode, to obtain a fast start-up time of 67 h. Modified anode material achieved a maximum load voltage of 0.62 V along with significant enrichment of the Geobacter genus. Consequently, the nano-Fe₃C anode exhibited an exceptional power density of 2316 mW m⁻² in the acetate-fed MFCs, which was higher than the reported studies involving Fe₃C-based non-graphene anode materials. The nano-Fe₃C@C material is a promising and sustainable anode for MFCs in wastewater treatment and renewable energy generation. Current findings have opened a new gateway for the preparation of other dispersive, durable, and high-performance metal-based materials for MFCs and bioelectrochemical sensors.

微生物燃料电池（MFC）是利用废水中的产电提取可再生能源的创新装置。MFC的性能主要取决于外放电极与阳极材料之间的电子转移效率。在这项工作中，将石墨碳层封装的碳化铁（Fe ₃ C）纳米粒子嵌入生物炭（纳米Fe ₃ C@C阳极）中，制备作为MFC的无粘合剂阳极材料。封装的碳层可以避免Fe ₃ C纳米粒子与电解液的直接接触，从而有效抑制纳米粒子的溶解和过度聚集，在10-70 nm范围内抑制率超过96%。此外，这种结构增强了Fe _{3之间的界面接触。}C 纳米粒子和生物炭基质，与 SC 和 CC 阳极相比，电荷转移电阻 (R _{ct ) 显着降低至 39.30 Ω。}这种混合结构还促进了纳米Fe ₃ C阳极外生电的生物相容性和细胞外电子转移（EET），获得了67小时的快速启动时间。改性阳极材料实现了 0.62 V 的最大负载电压，同时显着富集了地杆菌属。因此，纳米Fe ₃ C阳极在醋酸盐供给的MFC中表现出2316 mW m ^-2的出色功率密度，这高于报道的涉及Fe ₃ C基非石墨烯阳极材料的研究。纳米Fe ₃C@C 材料是一种有前途且可持续的阳极，适用于废水处理和可再生能源发电中的 MFC。目前的研究结果为制备用于 MFC 和生物电化学传感器的其他分散、耐用和高性能金属基材料开辟了新的途径。