Nano-Fe3C@2D-NC@CC as anode for improving extracellular electron transfer and electricity generation of microbial fuel cells

Highlights: : • A binder-free anode is developed by assembling 2D Zn-Fe-MOF arrays on carbon cloth. • The anode features nano-Fe₃C particles highly dispersed on 2D N-doped carbon arrays. • Highly dispersed nano-Fe₃C particles improves extracellular electron transfer. • Superior power density is harvested when the anode is applied in microbial fuel cells. -- Abstract: : Microbial fuel cells (MFCs) are attractive because they can harvest energy from sewage, but challenge remains in achieving valuable power density. To address this issue, we develop a novel binder-free anode, Nano-Fe₃C@2D-NC@CC, by assembling 2D Zn-Fe-MOF arrays on the fibers of carbon cloth and subsequently carbonizing MOF. This fabrication results in a unique configuration that nano-Fe₃C particles are highly dispersed on N-doped carbon arrays vertically standing on carbon fibers. The standing 2D arrays not only benefit bacterial adhesion but also guarantee nano-Fe₃C particles with abundant sites for the charge transfer between bacteria and anode. Consequently, a superior power density (1606 ± 52 mW m ^{− 2}) is harvested when the resultant Nano-Fe₃C@2D-NC@CC is evaluated as the anode in MFCs based on a mixed bacterium culture. The facile fabrication of Nano-Fe₃C@2D-NC@CC paves a promising path for the application of MFCs in large scale.