Fabrication and electrochemical study of K(1,1′- (1,4 Butanediyl)dipyridinium)2[PW11O39Co(H2O)]/MWCNTs-COOH nanohybrid immobilized on glassy carbon for electrocatalytic detection of nitrite

Abstract

• Fabrication an electrochemical sensor based on (bdpy)PW 11 Co/MWCNTs-COOH. • (bdpy)PW 11 Co/MWCNTs-COOH/GCE showed excellent electrocatalysis towards NO 2 – . • (bdpy)PW 11 Co/MWCNTs-COOH/GCE exhibited good selectivity and stability. • The LOD of NO 2 – is about 0.63 µmol L −1 with sensitivity of 17.9 µA mM −1 . A nanocomposite modified glassy carbon electrode (GCE) based on K(1,1′-(1,4-Butanediyl) dipyridinium) 2 [PW 11 O 39 Co(H 2 O)]/carboxyl functionalized multi-walled Carbon Nanotubes ((bdpy)PW 11 Co/MWCNTs-COOH/GCE) was fabricated by electrodeposition method. TEM images demonstrated that ((bdpy)PW 11 Co nanoparticles were dispersed uniformly on the surfaces of MWCNTs-COOH or their interlayers with a diameter of 8.5 nm. The morphological, electrochemical, and electrocatalytic behaviors of the modified electrode were investigated by field emission scanning electron microscopy (FE-SEM) combined with energy-dispersive X-ray spectroscopy, cyclic voltammetry, and amperometry techniques. The FE-SEM images well showed immobilization of (bdpy)PW 11 Co/MWCNTs-COOH on GCE by deformation of the mirror surface to the rough surface. The electrochemical test results confirmed that (bdpy)PW 11 Co/MWCNTs-COOH/GCE has good stability and remarkable electrocatalytic behavior toward the reduction of nitrite ion. The proposed sensor displayed a linear range of 10–1600 µmol L −1 with LOD of 0.63 µmol L −1 (S/N = 3), and sensitivity 17.9 µA mM −1 . Moreover, the results of the electrochemical experiments indicated that this sensor has an excellent selectivity, good reproducibility, and repeatability, high stability, as well as analytical performance in real samples.