Structural and defect engineering of W-doped NiCo2S4 nanorods: Sensitive and selective electrocatalyst for detection of promethazine hydrochloride and theoretical insights

Herein, a single-step hydrothermal approach is used to synthesize structurally and defect-engineered W-doped NiCo 2 S 4 nanorods (W-NCSNRs) as a sensitive electrocatalyst for antihistamine drug promethazine hydrochloride (PMZ-HCl) detection. The defect formation in W-NCSNRs is confirmed by X-ray diffraction, transmission electron microscopy, and Raman peak shift and broadening. The electrochemical activities of the W-NCSNRs modified glassy carbon electrode (W-NCSNRs/GCE) and NiCo 2 S 4 nanoneedles modified glassy carbon electrode (NCSNNs/GCE) were examined using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Under optimal conditions, the W-NCSNRs/GCE detects PMZ-HCl effectively with improved electrochemical active surface area and electrochemical response compared to NCSNNs/GCE and bare GCE. PMZ-HCl’s molecular-level and electronic properties were studied using density functional theory. Further, W-NCSNRs/GCE shows good detection sensitivity of 4.1606 µA/µM/cm 2 , with a lower limit of detection of 0.0161 µM in the linear range of 0.05 to 6.30 µM. Owing to the W-NCSNRs/GCE's simple configuration, enhanced catalytic activity, long-term stability, repeatability, and reproducibility towards the electrochemical activities of PMZ-HCl, with a good recovery rate (in biological and environmental samples), this could be a possible substitute for PMZ-HCl detection and quantification.