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

Abstract

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 Ω, which is 39% lower than that (150 Ω) 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 (i₀). 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.