Bimetallic ZIF-derived heteroatomic-doped bioanode catalysts for enhanced power production in microbial fuel cells

Binary composite nanoparticles (NPs) are considered anode materials with development potential. Herein, we synthesized two composite NPs, namely Mn-Co3O4/NPs and Mn-Co9S8/NPs, by codoping O, S and C based on bimetallic zeolitic imidazolate framework (Co-Mn-ZIF) precursors. The modified carbon felt (CF) Mn-Co3O4/NPs@CF and Mn-Co9S8/NPs@CF integrated into the microbial fuel cells (MFCs) exhibited the highest volume power densities of 4.58 ± 0.11 and 5.12 ± 0.15 W m−3, respectively, which were higher than that of the precursor anode Co-Mn-ZIF (2.70 ± 0.07 W m−3). In addition, microbial community structure analysis showed that the Mn-Co3O4/NPs@CF and Mn-Co9S8/NPs@CF bioanodes were substantially enriched with electricity-producing bacteria such as Geoalkalibacter, Thermovirga, and Desulfuromonas. The synergistic effect of the binary metal composites along with their oxides and sulfides, facilitated the extracellular electron transfer and biofilm formation. These results demonstrate the advantageous properties of heteroatom-doped binary metal NPs, including high electrical conductivity and good biocompatibility. These NPs serve as excellent anode materials for fabricating high-performance MFCs.