Bio-electrocatalyst Fe3O4/Fe@C derived from MOF as a high-performance bioanode in single-chamber microbial fuel cell

As a promising green and storage/conversion technology, the microbial fuel cell (MFC) was generally restricted by the lower power density in application. Three carbonized derivatives of the same precursor metal organic framework (MOF) MIL-53(Fe) were prepared via carbonization at 385 ℃, 600 ℃ and 750 ℃ in argon atmosphere. Experiments showed that carbonized MIL-53(Fe) (CM53) derivative at 750 ℃ produced Fe3O4/Fe@C structure and revealed the best performance as bioanode in MFC. As anticipated, the MFC with CM53–750/Ti anode demonstrated superb maximum power density of 1179.08 mW/m2, which was 88.04% and 36.24% higher than that of MFC with CM53–385/Ti and CM53–600/Ti anode. Moreover, the charge transfer resistance of CM53–750/Ti (0.23 Ω) bioanode in MFC was 90.49% and 87.29% lower than that of CM53–385/Ti (2.42 Ω) and CM53–600/Ti (1.81 Ω) in MFC. The BCA method and high-throughput sequencing proved that CM53–750/Ti bioanode exhibited good biocompatibility and the function of screening the dominant bacteria for electricity generation. The results were mainly attributed to the synergistic effect of derived carbon, iron and Fe3O4 nanoparticles (NPs). Fe3O4 NPs and porous rod-like carbon promoted the enrichment and cultivation of microorganisms on the anode surface, while Fe NPs provided an efficient path for the transmission of extracellular electrons. This article proved that the carbonized derivatives of MOF have application potential in MFC.