Lowering the potential of electroenzymatic glucose oxidation on redox hydrogel-modified porous carbon electrode

Herein, we demonstrate high current densities per projected surface area for the electroenzymatic oxidation of glucose at low potential using a hierarchically structured electrode based on MgO-templated carbon. The modified electrode was prepared by assembling glucose oxidase (GOx) with an osmium-based redox polymer with a low formal potential (−0.03 V vs. Ag|AgCl), in which Os complexes are tethered to the polymer backbone via a 13-atom alkyl chain and a crosslinker. A glucose oxidation current density of 15 mA cm−2 was measured at 0 V vs. Ag|AgCl at 37 °C and pH 7, with a plateau value of 50 mA cm−2 at 0.3 V. The hydrogel electrodes composed of the same redox polymer and FAD-dependent glucose dehydrogenase delivered only 10% of the current densities obtained with the GOx electrode.