Reduced Graphene Oxide-Conjugated Urchin-Like NiCo2O4Nanostructures for Individual Detection ofo-Nitro andp-Amino Phenol

This work introduced a facile synthesis method of reduced graphene oxide-conjugated urchin-like NiCo 2 O 4 nanostructures via a simple, cost-effective, and environmental-friendly one-pot hydrothermal method. The as-prepared rGO-NiCo 2 O 4 nanocomposites were used to fabricate 3-aminopropyltriethoxysilane-modified glassy carbon electrode (GCE/APTES/rGO-NiCo 2 O 4 ) for ultrasensitive electrochemical detection of o -nitro ( o -NP) and p -amino ( p -AP) phenols. The structure and morphology of the nanocomposite were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. Electrochemical experiments revealed that the nanocomposite exhibited remarkable electrochemical performances. A linear relationship is observed with the differential pulse voltammetry experiment between the peak currents and the concentrations in the ranges of 5.0 × 10 -9 to 5.0 × 10 -7 M ( R 2 = 0.996) and 1.0 × 10 -6 to 2.5 × 10 -5 M ( R 2 = 0.992) for o -NP and of 1.0 × 10 -8 to 5.0 × 10 -7 M ( R 2 = 0.996) and 1.0 × 10 -6 to 1.0 × 10 -4 M ( R 2 = 0.987) for p -AP. The calculated detection limits (S/N = 3) are 5.0 × 10 -9 M and 1.0 ×10 -8 M for o -NP and p -AP, respectively. Furthermore, a very high recovery percentage is obtained with the proposed sensor after successful application in the determination of target analytes in tap water samples.