Development of a Conductive Biomimetic Nanocomposite Anode for Improved Microbial Fuel Cell Efficiency

Abstract

Microbial fuel cells (MFCs) have gained attention as a renewable energy option due to the utilization of microbes as catalysts for the oxidation of natural substrates. In order to increase the practical application of MFC technology, the overall system must enhance power output and lower operational costs. More specifically, the bacteria must dock on the electrode surface to allow for efficient electron transfer mechanisms. In efforts to increase productive bacteria-surface interactions, this work focuses on the synthesis of a conductive, cellulose-based nanocomposite for use as anodic electrodes. The nanocomposite material was non-covalently modified through the incorporation of sugar-functionalized TiO2 nanoparticles. The relationship between conductivity and biocompatibility was explored in order to optimize the interactions between the synthesized electrodes and Escherichia coli (E. Coli). Power production using the composite electrodes was correlated to biofilm formation and cell proliferation via atomic force microscopy (AFM) and live/dead stain, respectively. The composite electrode materials have shown increased electrical response over traditional carbon cloth when used as anodes under dye-mediated conditions. Additionally, the sugar-functionalized composites showed increased bacterial adsorption and enhanced cell viability indicating more intimate contact between the microbes and the electrode surface. Initial results also suggest photochemical activity using sugar, polyaniline modified TiO2 nanoparticles embedded within the cellulose matrix resulting in responsive fuel cell behavior. Future work aims to incorporate supramolecular structures, such as β-cyclodextrin, to constrain dye absorption to the material surface and potentially increase the electrical response and longevity of the fuel cell system.