Biosynthesized <i>α</i> -MnO ₂ -based polyaniline binary composite as efficient bioanode catalyst for high-performance microbial fuel cell

Abstract

Microbial fuel cell (MFC) has novel technological advances in simultaneous power generation and wastewater treatment applications. In this study, low-cost biosynthesized α-MnO2 nanoparticles integration with conducting polyaniline (PANI) matrix to form α-MnO2/PANI hybrid nanocomposite was fabricated by in situ polymerization method. The prepared material was characterized through UV-Vis spectroscopy, XRD, FTIR, TGA-DTA, DSC, SEM, cyclic voltammetry, and impedance spectroscopy. MFC performance study was done by using an external resistance in the range of 100 Ω–100 kΩ. The continuous test on bare pencil graphite electrode (PGE), α-MnO2/PGE, PANI/PGE, and α-MnO2/PANI/PGE were evaluated in glucose-fed-Escherichia coli-based MFC. It was found that α-MnO2/PANI/PGE produces a maximum power and current densities of 426.26 ± 38.89 mW m−2 and 2485.51 ± 397.31 mA m−2, respectively. This was 6.5 and 5.7-fold higher in power and current densities than unmodified PGE. The maximum chemical oxygen demand produced by hybrid composite modified anode during closed circuit voltage or with external resistance and open circuit voltage (OCV) (circuit without connecting external resistance) measurements were found to be 88.19% and 92.27%, respectively. A maximum of 650.61 ± 10.11 mV OCV was obtained by α-MnO2/PANI/PGE while 222.36 ± 8.16 mV of OCV was generated by PGE.