A high-performance PdO@SWCNTs/NiO nanocomposite-based electrochemical sensor for sensitive and selective detection of hydroquinone

Abstract

In this study, a highly sensitive electrochemical sensor with low cost is designed for determining Hydroquinone (HQ) by modifying glassy carbon (GC) electrodes with PdO@SWCNTs/NiO nanocomposite. Herein, a semiconductor metal oxide (NiO) is decorated with single-walled carbon-nanotubes (SWCNTs) and palladium oxide (PdO), using a simple ultrasonication procedure, followed by a photo-reduction approach to achieve the final PdO@SWCNTs/NiO nanocomposite. The synthesized nanocomposites' morphological and structural characteristics were effectively investigated by High-Resolution Transmission Electron Microscope (HR-TEM), Field Emission Scanning Electron Microscope (FE-SEM), X-ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS) techniques. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to evaluate the electro-catalytic performance. For the sensing studies, Differential Pulse Voltammetry (DPV) and amperometric (i-t) techniques were successfully employed, where DPV demonstrated superior sensitivity with 0.74 μAμM⁻¹cm⁻² and a low limit of detection (LOD) of 0.29 μM within the concentration range of 10 μM–495 μM of HQ. Moreover, in the amperometric technique, the designed sensor revealed superb results with a sensing concentration ranging from 60 μM to 1920 μM and a sensitivity of 0.35 μA $\mu$ M⁻¹cm⁻² with a detection limit of 0.62 μM. Furthermore, the developed sensor exhibits acceptable reproducibility, repeatability, and stability. Under experimental conditions, the examined sensor showed outstanding selectivity towards HQ in the presence of both inorganic and organic interference components. Moreover, in real-world analysis of samples, the developed sensors recover HQ with a reliable Relative Standard Deviation (%RSD) value.