Amperometric sensor based on carbon dots decorated self-assembled 3D flower-like β-Ni(OH)2 nanosheet arrays for the determination of nitrite.

Abstract In the present work, self-assembled 3D flower-like β-Ni(OH) 2 @CDs hybrid nanostructures were synthesized by a simple and low-cost procedure using the CTAB-assisted hydrothermal method. Characterization of synthesized nanocomposite was performed by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), FT-IR and electrochemical techniques. Then, this product was used to fabricate a new nitrite sensor by drop casting 5 μl of its suspension (5 mg/mL prepared in Milli-Q water) on a cleaned glassy carbon electrode surface. The effects of some parameters on the sensor response toward the electro-oxidation of nitrite such as pH, and scan rate were evaluated and optimized to achieve higher sensitivity. The novel amperometric sensor exhibited excellent electrocatalytic activity toward the electro-oxidation of nitrite in the linear range of concentration 2.5 × 10−6 M to 1.2 × 10−3 M with a low detection limit of 0.03 μM (S/N = 3) and very good detection sensitivity of 647.8 μA mM−1 cm−2. The favorable advantages such as good repeatability and reproducibility, high sensitivity, long-term stability and anti-interference make this sensor very attractive for on-site environmental monitoring of nitrite in water samples with satisfied recovery. Graphical abstract Image 1 Highlights • Self-assembled 3D flower-like β-Ni(OH) 2 @CDs was synthesized by the CTAB-assisted hydrothermal method at low temperature. • The important advantages of this synthesis are the simplicity, green wet-chemicals method and low temperature. • The fabricated sensor based on β-Ni(OH) 2 @CDs can enhance electrocatalytic activity towards the oxidation of nitrite. • The main advantage of this sensor is a wide linear range with very low detection limit compared with other sensors. • The unique features of the β-Ni(OH) 2 @CDs make it as a promising candidate to fabricate sensors applicable in environmental field. [ABSTRACT FROM AUTHOR]