EDTA mediated microwave hydrothermal synthesis of WO3 hierarchical structure and its photoactivity under simulated solar light

• Cauliflower like WO3 hierarchical structure was obtained.
• EDTA favored the formation of hierarchical structure.
• Oxygen vacancies and high degree of crystallinity enhanced the photoactivity.

In this paper, we report a facile microwave hydrothermal synthesis of WO3 hierarchical structure in presence of disodium salt of ethylenediaminetetraacetic acid (EDTA) as a complexing agent and its photoactivity for the degradation of rhodamine B (Rh B) under simulated solar light irradiation. The synthesized WO3 samples were structurally, morphologically and optically characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and Brunauer–Emmett–Teller (BET) surface area analysis. The result revealed that the addition of EDTA leads to the controlled aggregation of WO3 nanoparticles having high crystallinity with monoclinic structure and creates oxygen vacancy in the WO3 lattice. Moreover, at high concentration of EDTA, cauliflower like hierarchical structure was formed when the optimum concentration of EDTA reaches to 0.5 mol% at pH 6 and exhibited best photoactivity for the Rh B degradation. These results indicate that the WO3 hierarchical structures with oxygen vacancies are potential materials for effective mineralization of Rh B, one of the hazardous pollutants.