Reduced Graphene Oxide-Conjugated Urchin-Like NiCo(2)O(4) Nanostructures for Individual Detection of o-Nitro and p-Amino Phenol

[Image: see text] 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.