Performance improvement of the glucose oxidation reactions using methyl red mediator

A new catalyst promoting an overall anodic oxidation reaction is suggested. In this catalytic structure, glucose oxidase (GOx) is immobilized onto polyethyleneimine (PEI) and carbon nanotube (CNT) (CNT/PEI/GOx) before polymerized methyl red (PMR) mediator coupled with PEI is further entrapped onto the CNT/PEI/GOx to complete CNT/PEI/GOx/[PEI-PMR]. With this, entrapped mediator-based electron transfer is well established. According to the related characterizations, when the glucose is used as reactant, overall oxidation reactions including glucose oxidation reaction are significantly improved by synergetic effect between GOx as a catalyst and PMR as an entrapped mediator. The optimal amount of embedded PMR determines the overall oxidation reaction rate because the amount of PMR that is obtained from the methyl red (MR) concentration of 3 mg mL(-1) can maximize the electron shuttling effect between GOx and electrode, followed by the overall oxidation reaction rate. Based on this, it is shown that CNT/PEI/GOx/[PEI-PMR3] is the best catalytic structure for promoting the overall oxidation reaction. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.