Synthesis, characterization of flower-like Pt/Bi₂WO₆ microcrystals and their high visible lightphotocatalytic performance

A series of 1.5~2 μm Pt/Bi₂WO₆ composite microflowers were synthesized by a hydrothermal synthesis combination with photo-deposition method. The as-synthesized microflowers were characterized by powder X-ray diffraction (XRD), N₂-physical adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra (DRS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR).The photocatalytic performance of the catalysts was evaluated by the consecutive photocatalytic degradation of acid orange II dye under visible light (λ > 420 nm) irradiation. The results showed that these hierarchical Pt/Bi₂WO₆ composite microflowers have superior texture property in aqueous photocatalytic reactions. Moreover, the deposition of optimal amount of 1% Pt brings about 2.8 times increase in activity. The deposited Pt NPs over Bi₂WO₆ nanosquares enhance the visible light absorption due to the surface plasmon resonance absorption, decrease the recombination rate of e^-/h⁺ pairs and promote ·OH radicals production, hence largely boosting the photocatalytic activity. Moreover, the unique hierarchical structures of Pt/Bi₂WO₆ microflowers benefit their separation and recycle in aqueous photocatalytic reactions, and utilization efficiency of the catalyst has been improved.