Carbon nanotube–ionic liquid composite gel based high-performance bioanode for glucose/O2 biofuel cells

Abstract

An easy-operation and high-performance bioanode based on a composite gel of carbon nanotubes (CNTs) and an ionic liquid (IL) was developed for a glucose/O₂ biofuel cell (BFC). Ferrocenecarboxaldehyde (Fc) was used as the mediator and was covalently immobilized on the ethylenediamine (EDA)-functionalized CNTs (CNTs-EDA). Glucose oxidase (GOD) was conveniently incorporated into the composite gel by simply grinding GOD into the CNTs-Fc/IL gel. The resulting electrode (GOD@CNTs-Fc/IL gel modified glassy carbon (GC) electrode) exhibited good catalytic activity and stability towards glucose oxidation. For the assembled glucose/O₂ BFC with the GOD@CNTs-Fc/IL gel modified GC electrode as the bioanode and a commercial E-TEK Pt/C modified GC electrode as the cathode, the open circuit potential is 0.66 V and a maximum power density of 60 μW cm⁻² can be achieved at 0.23 V. The ease of preparation, high activity and stability of the enzyme electrode based on the CNTs/IL gel can bring about a relatively general approach for fabricating biofuel cells and biosensors.