Pentacyanoferrate and Bilirubin Oxidase-bound Polymer for Oxygen Reduction Bio-cathode

Abstract

Pentacyanoferrate-polymer (PVI[FeIII(CN)5]) was synthesized from potassium hexacyanoferrate (II) and a backbone polymer, poly(1-vinylimidazole) (PVI). Bilirubin oxidase (BOD) from Myrothecium verrucaria and PVI[Fe(CN)5] were cross-linked with poly(ethylene glycol) diglycidyl ether. BOD-PVI[Fe(CN)5]-modified glassy carbon electrode showed a sigmoidal wave of a catalytic four-electron reduction of dioxygen (O2) with a half-wave potential of 0.2 V vs. Ag|AgCl|KCl(sat.) in rotating disk voltammetry. The current density as high as 15 mA cm−2 was achieved by immobilization of BOD-PVI[Fe(CN)5] on carbon paper electrodes at 4000 rpm under O2-saturated conditions.