Aryl diazonium salts are coupling agents that assist in molecules attachment to interfaces for sensing purposes. Despite
not being fully explored and not yet widely applicable for cell-based sensors, the high stability of aryl diazonium salt
formed sensing system is highly favorable in biological applications. Carbon-based electrodes are the most commonly
used in aryl diazonium modification due to its post grafting stable C-C bond formation. Here, salt bridge based microbial
fuel cells (MFCs) were used to study on the effect of aryl diazonium modification on the anode graphite fibre brush. Aryl
diazonium salts were in situ generated by the diazonation of p-phenylenediamine with NaNO2 in HCl solution. The
electrochemical performance of the aryl diazonium modified graphite brush MFC was measured and compared with the
unmodified graphite brush MFC. The power output of the modified graphite brush bioanode was higher (8.33 W/m3
)
than the unmodified graphite brush (7.60 W/m3
) after 20 days of operation with ferricyanide as the catholyte. After 70
days of operation using phosphate buffer solution as the catholyte, the Pmax of modified brush was three times higher
(0.06 W/m3
) than of the unmodified brush (0.02 W/m3
), which indicates an enhanced binding towards the substrate that
facilitates a better electron transfer between the microbial and electrode surface.
Microbial fuel cells (MFCs) have a high potential application for simultaneous wastewater treatment and electricity
generation. However, the choice of the electrode material and its design is critical and directly affect their performance.
As an electrode of MFCs, the anode material with surface modifications is an attractive strategy to improve the power
output. In this study, stainless steel (SS) and carbon steel (CS) was chosen as a metal anode, while graphite felt (GF)
was used as a common anode. Heat treatment was performed to convert SS, CS and GF into efficient anodes for MFCs.
The maximum current density and power density of the MFC-SS were achieved up till 762.14 mA/m2
and 827.25 mW/m2
,
respectively, which were higher than MFC-CS (641.95 mA/m2
and 260.14 mW/m2
) and MFC-GF (728.30 mA/m2
and 307.89
mW/m2
). Electrochemical impedance spectroscopy of MFC-SS showed better catalytic activity compared to MFC-CS and
MFC-GF anode, also supported by cyclic voltammetry test.