High surface area 3D-MgO flowers as the modifier for the working electrode for efficient detection of 4-chlorophenol

Abstract

We report for the first time, magnesium oxide (MgO) 3D-flowers, synthesized by a simple reflux method. The synthesized MgO 3D-flowers were characterized by powder X-ray diffraction (PXRD), ultra-violet visible (UV-vis) spectroscopy, scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) mapping to confirm their purity, morphology and elemental composition. The synthesized MgO 3D-flowers had a very high specific surface area of 218 m² g⁻¹ as confirmed by the N₂ adsorption–desorption isotherm. These MgO 3D-flowers were employed as an electrode modifier for the construction of an electrochemical sensor to detect 4-chlorophenol (4-CP). The active surface area of the glassy carbon electrode (GCE) was modified with MgO 3D-flowers with the assistance of 0.1% Nafion (MgO 3D-flowers/GCE) and the MgO 3D-flowers/GCE sensor shows an excellent electrocatalytic behavior towards 4-CP. The constructed MgO 3D-flowers/GCE sensor exhibits the limits of detection (LOD) of 45 nM, 68 nM, and 52 nM, and sensitivities of 2.84 μA μM⁻¹ cm⁻², 5.94 μA μM⁻¹ cm⁻², and 10.67 μA μM⁻¹ cm⁻² in cyclic voltammetry (CV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV) techniques, respectively. The modified MgO 3D-flowers/GCE sensor displays excellent performance in terms of sensitivity, selectivity, repeatability and reproducibility. The excellent electrocatalytic activity of the proposed MgO 3D-flowers/GCE sensor was attributed to the high specific surface area, surface electron transfer ability and the presence of the edges/corner defects of MgO 3D-flowers.