Abstract
Graphene-based composites have been widely explored for electrode and electrocatalyst materials for electrochemical energy systems. In this paper, a novel composite material of the reduced graphene oxide nanosheets (rGON) with gold nanoparticles (NPs) (rGON-AuNP) is synthesized, and its morphology, structure, and composition are characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopic (FTIR), Raman, and UV-Vis techniques. To confirm this material’s electrochemical activity, a glucose oxidase (GOD) is chosen as the target reagent to modify the rGON-AuNP layer to form GOD/rGON-AuNP/glassy carbon (GC) electrode. Two pairs of distinguishable redox peaks, corresponding to the redox processes of two different conformational GOD on AuNP, are observed on the cyclic voltammograms of GOD/rGON-AuNP/GC electrode. Both cyclic voltammetry and electrochemical impedance spectroscopy are employed to study the mechanism of direct electron transfer from GOD to GC electrode on the rGON-AuNP layer. In addition, this GOD/rGON-AuNP/GC electrode shows catalytic activity toward glucose oxidation reaction.
Highlights
In the last several decades, research and development of carbon-based nanomaterials for electrodes and electrocatalysts in electrochemical energy conversion devices such as fuel cells, lithium batteries, metal-air batteries, lead-acid batteries, and supercapacitors have been given tremendous efforts for many applications [1,2,3,4,5]
glucose oxidase (GOD) adsorbs onto AuNP in different spatial orientations, and the two pairs of redox peaks might correspond to the redox processes of two different conformational GOD on AuNP
As shown in Scheme 1, graphene oxide nanosheets (GON)-AuNP composite is prepared according to the reference with some modification [23]
Summary
In the last several decades, research and development of carbon-based nanomaterials for electrodes and electrocatalysts in electrochemical energy conversion devices such as fuel cells, lithium batteries, metal-air batteries, lead-acid batteries, and supercapacitors have been given tremendous efforts for many applications [1,2,3,4,5]. One type of the advanced carbon materials, graphene-based ones with the morphology of one-atom-thick planar sheet which are comprised of sp2 -bonded carbon atoms, have attracted great attention because of their excellent intrinsic physical and chemical properties [6] Their ultra-large surface area and ultra-high electrical conductivity make them an alternative electrode and electrocatalyst material for electrode reactions in electrochemical energy technologies [7]. The FAD center is deeply buried inside GOD, the electron transfer between GOD and electrode is still facilitated by AuNP on the rGOD-AuNP composite Different from those reported one-pair of well-defined redox peaks in literatures [15,16,17,18,19,20], two-pairs of overlapped redox peaks are observed on the cyclic voltammograms of the GOD/rGON-AuNP electrode. The research results are helpful for better understanding the electrode behavior of GOD on graphene-based composite, which is crucial in developing advanced electrode materials for electrochemical energy devices
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