Bi2WO6/TiO2/Pt nanojunction system: A UV-vis light responsive photocatalyst with high photocatalytic performance

Aiming at enhancing photocatalysis through increasing light harvesting and improving quantum efficiency, a new Bi2WO6/TiO2/Pt composite photocatalyst was fabricated. Morphology characterization demonstrated that anatase TiO2 and metal Pt were orderly incorporated with Bi2WO6 nanosheets. UV-vis diffuse reflectance spectra and photocurrent measurements displayed that Bi2WO6/TiO2/Pt composite catalyst exhibited enlarged photoresponse range and improved photocurrent density. In the photodegradation experiments of Rhodamine B and bisphenol A under simulated sunlight (320 nm < lambda < 780 nm) irradiation, the Bi2WO6/TiO2/Pt composite presented the highest photocatalytic activity compared to the photocatalysts containing one- component (TiO2, Bi2WO6) or two-component (TiO2/Pt, Bi2WO6/Pt). The enhanced photocatalysis benefited from the increased light harvesting owing to the excitation of both TiO2 and Bi2WO6 and the high quantum efficiency due to the heterojunction between Bi2WO6 and TiO2 and the Schottky junction between TiO2 and Pt. The photocatalyitc mechanism analysis revealed that the superoxide radical originated from the electroreduction of dissolved oxygen with photogenerated electrons was the primary oxidant in Bi2WO6/TiO2/Pt photocatalysis, and the hydroxyl radical derived from the reaction of holes and H2O was also responsible for pollutant degradation. (C) 2015 Elsevier B.V. All rights reserved.