Pd nanoparticle-modified Bi2WO6 nanoplates used for visible-light-driven photocatalyst

Pd nanoparticles supported on Bi₂WO₆ nanoplates used for visible-light-driven photocatalyst were successfully synthesized by photoreduction deposition method under visible-light irradiation. Different analytical techniques including X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and photoluminescence spectroscopy revealed that face-centered cubic metallic Pd nanoparticles were uniformly loaded on top of orthorhombic Bi₂WO₆ nanoplates to form heterostructure Pd/Bi₂WO₆ nanocomposites. Photocatalytic activities of pure Bi₂WO₆ sample and heterostructure Pd/Bi₂WO₆ nanocomposites were studied through the photodegradation of rhodamine B (RhB) under visible-light irradiation. The photocatalytic efficiency of Bi₂WO₆ was increased to the highest by being loaded with 5 wt% Pd and then decreased by being loaded with 10 wt% Pd. The improved photocatalytic efficiency caused by high-efficiency diffusion and separation of photo-generated charge carriers was explained and can lead to superior photodegradation of RhB under visible-light irradiation.

     

Visible-light-driven heterostructure Ag/Bi2WO6 nanocomposites synthesized by photodeposition method and used for photodegradation of rhodamine B dye

Visible-light-driven heterostructure Ag/Bi₂WO₆ nanocomposites were prepared by transforming Ag⁺ ions into metallic Ag⁰ nanoparticles loaded on top of Bi₂WO₆ nanoplates under visible light irradiation for 1 h. XRD, XPS, SEM and TEM analyses indicated that spherical metallic Ag nanoparticles were uniformly dispersed on top of orthorhombic Bi₂WO₆ thin nanoplates. Rhodamine B (RhB) was used as a dye model for investigation of photocatalytic performance of Bi₂WO₆ nanoplates with different weight contents of Ag nanoparticles illuminated by visible radiation. In this research, 10% Ag/Bi₂WO₆ nanocomposites have the highest photocatalytic activity in the degradation of RhB at 94.21% within 210 min because of the rapid diffusion of electronic charge through the Schottky barrier between metallic Ag nanoparticles and Bi₂WO₆ thin nanoplates, good electrical conductivity of metallic Ag nanoparticles, inhibited recombination of charge carriers and enhanced photocatalytic activity of Ag/Bi₂WO₆ nanocomposites. Main active species of the photocatalysis and stability of the photocatalyst were also evaluated.