Fabrication of g-C₃N₄/WO₃ Nanocomposite for Efficient Visible Light Photocatalytic Degradation of Rhodamine B and Electrochemical Sensing of 2-Nitrophenol

In this study, a novel photocatalyst comprising graphitic carbon nitride (g-C₃N₄) and tungsten oxide (WO₃) in different weight ratios was fabricated through a facile synthesis method. The synthesized nanocomposites were characterized using various techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–vis spectroscopy to elucidate their structural and optical properties. The photocatalytic performance of the g-C₃N₄/WO₃ nanocomposite was evaluated for Rhodamine (RhB) degradation under visible light irradiation. Remarkably, the 3 wt % g-C₃N₄/WO₃ nanocomposite exhibited a superior degradation efficiency of 96% (rate constant ~ 0.02714 min⁻¹) compared to pure g-C₃N₄ and WO₃. The major role was played by both holes (h⁺) and superoxide anion radicals (•O₂⁻) in the degradation process. This performance is attributed to the synergistic effect between the two components, which facilitated efficient charge separation leading to decreased recombination of photo-generated electron–hole pairs, and improved light absorption. Additionally, the optimized nanocomposite was employed for electrochemical detection of 2-nitrophenol (2-NP), showcasing remarkable sensitivity (limit of detection ~ 0.22 µM) and selectivity towards 2-NP. This positions it as a promising candidate for environmental monitoring applications. In summary, this study underscores the potential of the g-C₃N₄/WO₃ nanocomposite in wastewater treatment as a visible light photocatalyst, alongside its utility in electrochemical sensing of organic pollutants.