Microwave–Assisted Synthesis of Nanoscale Tungsten Trioxide Hydrate with Excellent Photocatalytic Activity under Visible Irradiation

Abstract Tungsten trioxide hydrate (WO3⋅1/3H2O) nanoparticles (NPs) were prepared via a microwave–assisted synthetic pathway by using Na2WO4·2H2O and PdCl2 as precursors. Microstructure and morphology of as–prepared WO3⋅1/3H2O NPs were investigated through X–ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FT–IR) spectra, while porosity and bandgap through specific surface area and UV–vis absorption spectroscopy. It was found that Pd2+ ions played a crucial role in the formation of WO3⋅1/3H2O NPs, and thus a possible formation mechanism was proposed based on the growth processes. The photocatalytic property of WO3⋅1/3H2O NPs was evaluated on the basis of Rhodamine B (RhB) degradation in aqueous solutions under simulated visible irradiation. Photocatalytic experimental results indicated that as–prepared WO3⋅1/3H2O NPs exhibited much more superior photocatalytic activity by contrast to that of the commercial WO3.