Flexible Electrochemical Sensor for Hydrogen Peroxide Detection by Employing WO₃/g-C₃N₄ Nanostructures

This paper describes the fabrication of WO₃/g-C₃N₄ and use of a flexible carbon cloth (CC)-based nonenzymatic detection of hydrogen peroxide (H₂O₂). The WO₃/g-C₃N₄ was prepared using a hydrothermal method and characterized using various techniques such as field emission scanning electron microscopy (FESEM), powder X-ray diffraction (PXRD), Fourier transform Infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) analysis. Further, the electrodes were fabricated using CC as a flexible and conductive support and was modified with different samples of WO₃/g-C₃N₄ nanostructures (1-WO₃/g-C₃N₄ and 2-WO₃/g-C₃N₄). The electrochemical investigations revealed that the 1-WO₃/g-C₃N₄/CC, and 2-WO₃/g-C₃N₄/CC modified electrodes have strong electrocatalytic activity than WO₃ towards the detection of H₂O₂, which can be attributed to the surface properties, conductivity and resultant interactions of WO₃ and g-C₃N₄ in WO₃/g-C₃N_4. Furthermore, the 1-WO₃/g-C₃N₄/CC, and 2-WO₃/g-C₃N₄/CC demonstrated a sensitivity of 78 μA mM⁻¹ cm⁻² and 59 μA mM⁻¹ cm⁻², respectively, and were used to measure the concentration of H₂O₂ in the range of 0.003-0.03 mM. In addition, the LOD of the 1-WO₃/g-C₃N₄/CC, and 2-WO₃/g-C₃N₄/CC was estimated for the sensor as 2.07 μM and 2.53 μM, respectively. These findings suggest that the WO₃/g-C₃N₄ with high conductivity and stability has a promising future in the development of electrochemical sensors.