SnO2:PANI modified cathode for performance enhancement of air-cathode microbial fuel cell

SnO2:PANI composites were synthesized and used as cathode material to enhance oxygen reduction reaction (ORR) in an air-cathode microbial fuel cell (MFC). The ratios of SnO2:PANI composites were varied as 50:50 (5S:5 P), 40:60 (4S:6 P), 30:70 (3S:7 P), SnO2 (S:0), and PANI (0:P). Analytical techniques were used for physical characterization of composites Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Dynamic light scattering (DLS), and Transmission electron microscopy (TEM). Water uptake and wettability of electrodes were evaluated using contact angle method. It was found that coating improves the hydrophobicity of the electrode. Cyclic voltammetry (CV) showed that the modified electrode had moderate capacitance and Electrochemical impedance spectroscopy (EIS) revealed a reduction in internal resistance due to the modification of the electrode. Tafel analysis showed that the relative kinetic activity of the electrodes having 4S:6 P weight ratio was nearly 102 times more than that of the bare electrode. The highest power density of 65 mW m−2, which is nearly two times that of carbon felt, was obtained by the reactor containing 4S:6 P composite coated cathode. The results revealed that the 4S:6 P composite can be a promising option as a cathode catalyst for enhancing the performance of MFCs.