Comparison of influence of nanomaterials on a glassy carbon paste electrode-based bioanode in biofuel cells

Abstract

This paper presents a comparative study of nanomaterial modified glassy carbon paste electrodes (GCPEs) used as bioanodes in enzymatic biofuel cells. The developed bioanode electrodes were obtained by modification of composite GCPEs with glucose oxidase (GOx) and different nanomaterials like manganese(IV) oxide nanoparticle (MnO$_{2}$ np) and aluminum titanate (Al$_{2}$O$_{3}$-TiO$_{2})$ bimetallic nanostructure. These nanostructures were utilized in a GCPE-based enzymatic bioanode construction for the first time. P-benzoquinone mediator was used for the electron transfer between enzyme redox center and bioanode electrode where glucose analyte was used as substrate. A laccase-modified plain GCPE was used as biocathode electrode. Then these electrodes were combined in a membraneless biofuel cell (BFC). The power densities of single cell BFCs were 0.619 $\mu $W cm$^{-2}$ (at 34 mV) for the plain GCPE, 4.57 $\mu $W cm$^{-2}$ (at 76 mV) for the GOx/MnO$_{2}$ np/GCPE, and 1.41 $\mu $W cm$^{-2}$ (at 36 mV) for the GOx/Al$_{2}$O$_{3}$--TiO$_{2}$/GCPE. As a result, it has been observed that the MnO$_{2}$ np/GOx/GCPE exhibits the best power density. The current density value of this bioanode has also been examined and found to be 99.21 $\mu $A cm$^{-2}$ in phosphate buffer solution (pH 7) with maximum open circuit potential of 294 mV.