Synthesis, characterization and photocatalytic performance of rod-shaped Pt/PbWO4 composite microcrystals

Rod-shaped PbWO4 microcrystals of length >1 mu m were fabricated by a hydrothermal route and subsequent calcination. Pt nanoparticles (NPs) of different contents (0.5 wt%, 1 wt% and 2 wt%) were subsequently deposited on the PbWO4 microcrystals, producing robust Pt/PbWO4 composite microcrystals. The PbWO4 microcrystals and Pt/PbWO4 photocatalysts were characterized by X-ray diffraction, N-2 sorption measurements, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron, photoluminescence, Fourier-transform infrared, and ultraviolet-visible diffuse reflectance spectroscopies. The photocatalytic performances of the catalysts were evaluated by the consecutive photocatalytic degradation of acid orange II dye. The Pt/PbWO4 composite microcrystals exhibited high photocatalytic activity and stability. The deposition of Pt NPs produced surface plasmon resonance (SPR), which induced a large visible light absorption. A Pt NP content of 1-2 wt% resulted in an similar to 2 times increase in photocatalytic activity, compared with the activity of Pt/PbWO4. The crystal structure and high crystallinity of PbWO4 resulted in its favorable photocatalytic property, and the SPR effect of the Pt NPs promoted visible light harvesting. The Pt NPs also enhanced the separation of photo-generated electrons and holes, which further promoted the photocatalytic reaction. (c) 2015, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.