Development of polypyrrole nanotube coated with chitosan and nickel oxide as a biocompatible anode to enhance the power generation in microbial fuel cell

Abstract

In this work, polypyrrole nanotubes (PPy-NT) are prepared by using a soft template of methyl orange and applied as anode catalyst in single chamber microbial fuel cell (SMFC). The coating of chitosan over PPy-NT (CHI@PPy-NT) provides good biocompatibility, proven by the increase in power density of the CHI@PPy-NT anode based SMFC compared to PPy-NT anode based SMFC. With the objective for further improvement in electrochemical efficiency, PPy-NT are coated with chitosan along with nickel oxide (NiO/CHI@PPy-NT) through hydrothermal method. XRD, FTIR, and XPS studies are used to characterize the structural and functional groups of the prepared nanocomposite. Morphological features reveal that nickel oxide is uniformly dispersed in chitosan coated on the surface of polypyrrole nanotubes. Cyclic voltammetry characterization shows high oxidation peak for CHI@PPy-NT (−0.0282 mA) and NiO/CHI@PPy-NT (−0.0286 mA), in comparison to PPy-NT (0.00860 mA). The coating of stainless steel mesh (SSM) anode with NiO/CHI@PPy-NT generates power density of 755 mW m−2, which is 4.4 times higher than the power density for bare stainless steel anode (170 mW m−2). Additionally, the charge transfer resistance obtained from the bare SSM is 817 Ω, 4.9 times high than the NiO/CHI@PPy-NT (165.3 Ω) modified SSM anode based MFC.