Artificial Electron Mediator with Nanocubic Architecture Highly Promotes Microbial Electrosynthesis from Carbon Dioxide

Abstract

Microbial electrosynthesis (MES) is an emerging strategy for converting electrical energy into chemical energy. Many efforts have been made toward the enhancement of cathode-microorganism interactions and electron transfer by modifying cathodic materials; however, high electrochemical activity and good biocompatibility have often not been available at the same time in previously reported materials. Here, we deliver a novel MES bioreactor by designing a well-defined Prussian blue nanocube-modified carbon felt (PBNC-CF) as an artificial electron mediator-decorated cathode for organic molecule production from a CO2 source. Because of the rapid electronic transition between Fe2+ to Fe3+ atoms in a unit cell, PBNCs significantly improve the electrochemical activity of the cathode by dramatically increasing the electron supply to electroautotrophic microorganisms. This modification also enhances the biocatalytic activity by regulating the composition of microbial community with the accumulation of acetogens such as Acetobacterium and the reduction of the electron-transferring bacterium, Arcobacter. Furthermore, the hydrophilicity and positive charge of PBNCs improve cathodic biocompatibility and are conducive to the growth of biofilms on the electrode surface and internal fibers. This strategy provides a new direction for MES electrode modification, showing that the development of an artificial electron mediator-based cathode is significantly important to improve MES efficiency.

Carbon Fibers for Bioelectrochemical: Precursors, Bioelectrochemical System, and Biosensors

“…11 a Schematic diagram of the structure principle of MES; design of the artificial electron mediator-modified cathodes in the MES systems, schematic showing the design for the CF self-assembly with PBNCs and the biofilm growth on the modified cathode ( b ); reprinted with permission from Ref. [ 164 ]. Copyright 2020 American Chemical Society.…”

“…However, not all methods providing a positively charged surface have been successful: for instance, treating CF cloth with melamine or ammonia does not stimulate the electrical synthesis of acetate [ 163 ]. Tian et al [ 164 ] designed a Prussian blue nano-cube-modified carbon felt as an artificial electron dielectric modified cathode for producing organic molecules from CO 2 sources. Regulating the microbial community composition to improve the biocatalytic activity is a new direction in MES electrode modification, indicating that cathodes based on artificial electronic media should improve the MES efficiency [ 164 ] (Fig.…”

Microbial electrosynthesis: carbonaceous electrode materials for CO2 conversion

“…Microorganisms attached to the CF are thought to absorb electrons from the cathode surface directly or indirectly to reduce CO2 23 . By controlling the composition of the cathodic microbial community, the modified CF electrode could increase biocatalytic activity 88 . A modified CF improved the biocatalytic activity by changing the microbial population composition by increasing acetogens like Acetobacterium.…”

“…23 By controlling the composition of the cathodic microbial community, the modified CF electrode could increase the biocatalytic activity. 88 A modified CF improved the biocatalytic activity by changing the microbial population composition by increasing acetogens such as Acetobacterium.…”

“…23 By controlling the composition of the cathodic microbial community, the modified CF electrode could increase the biocatalytic activity. 88 A modified CF improved the biocatalytic activity by changing the microbial population composition by increasing acetogens such as Acetobacterium . A high rate of acetate production was ascribed to the improved biocompatibility for biofilm growth on the cathode surface and internal fibers.…”