Bio-power performance enhancement in microbial fuel cell using Ni-ferrite decorated anode

Microbial fuel cell (MFC) is an emerging field in biotechnology for bio-power recovery synchronizing with wastewater degradation. However, the bio-current generation is severely limited by the extracellular electron transfer (EET) from the bacteria to the anode. A nano spinel type NiFe2O4 decorated MFCs anode was designed, fabricated and optimized. The MFC with the 5% NiFe2O4 added anode delivered a maximum power density (MPD) of 806.4 mW m(-2), which was 26% higher than the value of 642 mW m(-2) obtained for the un-added one. The MFC polarization resistance equipped with the most appropriate amount (5%) of NiFe2O4 decorator was only 92 U, which is 39% lower than that (150 U) of the control. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and Tafel tests exhibited remarkable enhancement in kinetic activity towards the bio-catalytic anodic reaction, which was attributed to the lower charge transfer resistance, higher substrate oxidation rate and exchange current density (i(0)). Further increment of the modifier can give rise to some negative effect, possibly due to the inhibition of electron diffusion on the contact interface. The study suggests that non-precious NiFe2O4 can be a promising promotor for the development of high-performance MFCs.