Towards a high potential biocathode based on direct bioelectrochemistry between horseradish peroxidase and hierarchically structured carbon nanotubes

Abstract

Adsorption of horseradish peroxidase (HRP) on graphite rod electrodes sequentially modified with carbon microfibers (CMF) carrying carbon nanotubes in a hierarchically structured arrangement and finally pyrene hexanoic acid (PHA) for improving hydrophilicity of the electrode surface is the basis for the direct bioelectrocatalytic reduction of H₂O₂ at potentials as high as about +600 mV. The high-potential direct bioelectrocatalytic reduction of H₂O₂ is implying a direct bioelectrochemical communication between the Fe^IVO,P⁺˙ redox state known as compound I. The HRP loading was optimized leading to a current of 800 μA at a potential of 300 mV.