A 3D printed low volume hybrid enzyme fuel cell for low power applications

Abstract

Herein, the construction of a novel low volume, low power hybrid enzyme fuel cell is demonstrated. The anode of the fuel cell is constructed by electrografting para amino benzoic acid in neutral medium. This is done for anchoring a poly(1-vinylimidazole-co-allylamine) Os(bipy)2Cl polymer/glucose oxidase mixture in the anode. A change in orientation of the same molecule (para amino benzoic acid), during electrografting in acid medium is utilised for anchoring Prussian blue in the non-enzymatic cathode. A membraneless hybrid enzyme fuel cell employing these electrodes is developed where oxidation of glucose and reduction of hydrogen peroxide take place at the anode and cathode respectively. The novelty of this report is that the same zwitter ionic molecule has been electrografted in neutral and acid pH to bring about appropriate functionalities on rGO for catalyst immobilisation. Cost effective commercial 3D printing has been utilised for the construction of a low volume fuel cell container so as to house the electrodes and electrolytes. The fuel cell assembled is capable of delivering a low power density of ca. 16 μW/cm2 with a short circuit current density of 300μA/cm2 with the use of 1 cm2 anode and 4 cm2 cathode. With these construction and performance characteristics, the fuel cell is relevant as a power source for powering future remotely located sensor networks. Temperature dependent and shelf life studies of the constructed device also show the suitability of the device for powering IoT based sensors.