Preparation and Application of 2,4-Dichlorophenol Electrochemical Sensor Based on Nano-SnS/Multi-Walled Carbon Nanotubes Composite

Nano-SnS/multi-walled carbon nanotubes (MWCNTs) composite was prepared through homogeneous precipitation method, and the morphology and constitution were characterized by field emission scanning electron microscopy (SEM), X-ray powder diffractometer (XRD) and thermal gravimetric analyzer (TGA). Nano-SnS/MWCNTs composite (10 mg) was dispersed in 1.0 mL of 5% (volume fraction) perfluorinated resin solution by ultrasonic, and the modified electrode was obtained by dripping 8.0 μL of aliquot onto the surface of treated glassy carbon electrode (GCE), which was denoted as nano-SnS/MWCNTs/GCE. The electrochemical property of nano-SnS/MWCNTs/GCE was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) using nano-SnS/MWCNTs/GCE as working electrode, platinum wire electrode as counter electrode, and saturated calomel electrode as reference electrode, and the electrochemical behavior of 2,4-dichlorophenol (2,4-DCP) on nano-SnS/MWCNTs/GCE was studied. As shown by the results, nano-SnS/MWCNTs/GCE had obvious electrocatalytic effect and high selectivity for 2,4-DCP in phosphate buffer solution at pH 7.0. Linear relationship between the concentration of 2,4-DCP and the oxidation peak current by DPV response was kept in the range of 0.05-3.00 μmol·L^-1, with detection limit (3S/N) of 2.3×10^-8mol·L^-1. Test for recovery was made on the water sample by standard addition method, giving results in the range of 92.0%-101% for 2,4-DCP.