Construct α-FeOOH-Reduced Graphene Oxide Aerogel as a Carrier for Glucose Oxidase Electrode

A promising α-FeOOH-reduced graphene oxide aerogel (FeOOH-GA) has been prepared for the assembly of an enzyme electrode. The α-FeOOH-reduced graphene oxide aerogel was characterized by X-ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The results reveal that graphene oxide is reduced by Fe²⁺ ion and α-FeOOH nanorods anchored on the reduced graphene oxide sheet through the Fe-O-C bond. Analyses using scanning electron microscopy and the Brunauer-Emmett-Teller method show that FeOOH-GA displays a various and interconnected pore structure. The FeOOH-GA was used as a support material on the glass carbon electrode (GCE) for glucose oxidase (GOD). Electrochemistry properties and bioelectrocatalytic activities of Nafion/GOD/FeOOH-GA/GCE were achieved from cyclic voltammetry and electrochemical impedance spectroscopy. The results show that Nafion/GOD/FeOOH-GA/GCE maintains outstanding catalytic activity and electrochemical properties. The FeOOH-GA could immobilize GOD through the hydrophobicity of the reduced graphene oxide and hydroxide radical of α-FeOOH. Appropriate α-FeOOH and diversified pore structure are beneficial for electron transfer, enzyme electrode storage, and interfacial electron transfer rate. All results indicated that the α-FeOOH-reduced graphene oxide aerogel as a carrier could effectively immobilize the tested enzyme.