Preparation of a nonenzymatic electrochemical sensor based on a g-C3N4/MWO4 (M: Cu, Mn, Co, Ni) composite for the determination of H2O2

Abstract

Hydrogen peroxide (H₂O₂) has a significant effect on physiological activity. In the present research, a g-C₃N₄-based nanocomposite g-C₃N₄/MWO₄ (M: Cu, Mn, Co, Ni) was prepared via the precipitation–calcination method. A series of physicochemical characterizations, including X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), EDX mapping, and energy dispersive X-ray photoelectron spectrometry (XPS), were used to confirm the formation of the binary nanocomposite. The glassy carbon electrode (GCE) was modified with g-C₃N₄/MWO₄ to obtain a g-C₃N₄/MWO₄/GC electrode and used for H₂O₂ detection. The prepared g-C₃N₄/CuWO₄/GC electrode shows a significant electrochemical selectivity and sensitivity for the detection of H₂O₂. The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) analyses also affirmed the ability of the prepared g-C₃N₄/CuWO₄/GC electrode for the reduction of H₂O₂. The synergetic effect between g-C₃N₄ and CuWO₄ is considered to be a substantial factor in the impressive electron transfer path and assists the capture of H₂O₂ in the binary composite. Under optimized conditions, g-C₃N₄/CuWO₄/GCE displayed superior sensing features, containing a wide linear range of up to 5.2 mM, a low detection limit of 0.4 μM, a high sensitivity of 35.91 and 11.02 μA mM⁻¹ cm⁻², and a high selectivity against some usual biomolecules. These results suggest that it is applicable as a reputable electrochemical H₂O₂ sensor.