Gold nanoparticles decorated on reduced graphene oxide as a supporting material for enzymatic bioanode

In this work, Au nanoparticles were synthesized using eco-friendly protocol and then supported on reduced graphene oxide (rGO) nanosheets through in-situ polymerization of indole (In), focusing on their electrochemical efficiency against glucose oxidation in glucose-based biofuel cells (glucose/O2). The bioanode was fabricated by applying ferritin (Frt) and glucose oxidase (GOx) on the glassy carbon electrode (GCE) followed by deposition of Au@rGO/PIn nanocomposite. The physical characterizations such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), and scanning electron microscopy (SEM), have revealed the successful synthesis of Au@rGO/PIn nanocomposite. In addition, the electrochemical behavior of different modified bioanodes were analyzed using linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The modified bioanode Au@rGO/PIn/Frt/GOx attained a maximum current output of 7.2 mA cm−2 at the optimum glucose concentration of 50 mM in phosphate buffer solution (PBS) as an electrolyte. However, the obtained result is not the highest current density as reported in the literature but the materials are cost effective and method is easier and ecofriendly. This suggests that 3D fabricated bioanode could be used in enzymatic biofuel cell (EBFC) applications and allied fields, such as biosensors and bioreactors.