Rapid elimination of thiamethoxam insecticide under visible light using novel Au nanoparticles/CdSe/WO3 ternary nanocomposite

Abstract

In this study, we have created a unique ternary photocatalyst using WO3 nanostructures in conjunction with CdSe and gold nanoparticles (Au NPs), which exhibits remarkable efficacy in purifying contaminated water under visible light. The Au, CdSe, and WO3 assembled ternary photocatalyst was synthesized through ultrasonication followed by a photoreduction process. The X-ray diffraction (XRD) analysis confirmed the presence of monoclinic WO3, hexagonal CdSe, and Au NPs in the ternary photocatalyst. Structural analysis and elemental composition were further substantiated through X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR) studies. Transmission electron microscopy (TEM) examinations revealed irregularly shaped Au NPs (5–15 nm), CdSe, and WO3 particles. Diffuse reflectance studies demonstrated a reduction in the band gap energy of the Au@CdSe/WO3 nanostructures. The Au@CdSe/WO3 ternary photocatalyst exhibited remarkable efficiency in the photocatalytic degradation of thiamethoxam (TXM) insecticide and methylene blue (MB) dye under visible light. It achieved an impressive 94.13 % removal efficiency for TXM in just 40 min, which was ∼2.04 more efficient than undoped WO3. Additionally, the Au@CdSe/WO3 nanostructures successfully decolorized MB dye under visible light within 14 min. This exceptional photocatalytic performance can be attributed to the increased surface area, enhanced light absorption capacity, and improved photo-induced carrier transfer with efficient separation behavior, as evidenced by photoluminescence and photocurrent transient analyses.