Synthesis of hierarchical hetero-composite of graphene foam/alpha-Fe2O3 nanowires and its application on glucose biosensors

In this study, graphene foam/hematite (GF/alpha-Fe2O3) nanowire arrays hetero-structured nanocomposite (HNC) electrode was synthesized in a hierarchical manner where each constituent had its own function. The synthesis of continuous, high crystallinity and intact graphene layers on the surface of Ni foam was carried out via chemical vapor deposition (CVD) and there was no significant deterioration after Ni removal. Acting as an active backing layer, the GF provided a large surface area with high charge transfer capacity, thus facilitating the high electron transfer rate and increased electrochemical response. Hydrothermal synthesis yielded alpha-Fe2O3 nanowires with an average length of 400-450 nm. XPS results showed that the HNC sample was mostly composed of alpha-Fe2O3 phase. Finally, HNC electrode was applied for the construction of an electrochemical glucose biosensor. The increased surface area of the electrode facilitated immobilization of large amounts of glucose oxidase (GOx). Based on the active surface area of the electrode, the limit of detection and sensitivity of the biosensor were calculated to be 71.6 mu M and 20.03 mu AmM(-1)cm(-2), respectively. The high sensitivity and selectivity of HNC for the detection of glucose demonstrated that the synthesized nanocomposite material is a promising material to construct high sensitive biosensors for the detection of biologically relevant molecules. (C) 2021 Elsevier B.V. All rights reserved.