Decoration of graphene nano platelets with gold nanoparticles for voltammetry of 4-nonylphenol

To decorate graphene nano platelets (GNPs) with uniform, non-aggregated, and well-distributed gold nanoparticles (Au NPs) as well as to improve the stability of GNPs on the electrode surface, a one step in situ co-electrodeposition procedure has been developed using a mixture of sol-gel, β-cyclodextrin (β-CD), and the gold precursor of HAuCl4. The in situ co-electrodeposited Au NPs have been characterized using scanning electron microscope and transmission electron microscope. Based on the composite of sol-gel, β-CD, Au NPs, and GNPs, a modified electrode has been constructed. After its characterization using voltammetry and impedance, voltammetry of 4-nonylphenol has been investigated on such an electrode, revealing an irreversible, adsorption-controlled, one-electron-and-one-proton involved oxidation process. The oxidation peak current is much enhanced. This enhancement is interpreted as a synergistic effect among GNPs, Au NPs, sol-gel, and β-CD. Using this electrode, a wide linear range (0.01-1.0 μM) and a low detection limit (down to 3.0 nM) for the monitoring of 4-nonylphenol have been achieved. Such a stable electrode is therefore promising for the reproducible and sensitive monitoring of 4-nonylphenol in the environment.

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