Electrochemical Pretreatment of Amino-Carbon Nanotubes on Graphene Support as a Novel Platform for Bilirubin Oxidase with Improved Bioelectrocatalytic Activity towards Oxygen Reduction

The electrochemical conditioning of aminocarbon nanotubes (CNTs) on a graphene support in an alkaline solution is used to produce -NHOH as hydrophilic functional groups for the efficient immobilization of bilirubin oxidase enzyme. The application of the immobilized enzyme for the direct electrocatalytic reduction of O-2 is investigated. The onset potential of 0.81 V versus NHE and peak current density of 2.3 mAcm(-2) for rotating modified electrode at 1250 rpm, indicate improved biocatalytic activity of the proposed system for O-2 reduction.