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

Abstract

Abstract Aiming at enhancing photocatalysis through increasing light harvesting and improving quantum efficiency, a new Bi 2 WO 6 /TiO 2 /Pt composite photocatalyst was fabricated. Morphology characterization demonstrated that anatase TiO 2 and metal Pt were orderly incorporated with Bi 2 WO 6 nanosheets. UV–vis diffuse reflectance spectra and photocurrent measurements displayed that Bi 2 WO 6 /TiO 2 /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 λ 2 WO 6 /TiO 2 /Pt composite presented the highest photocatalytic activity compared to the photocatalysts containing one-component (TiO 2 , Bi 2 WO 6 ) or two-component (TiO 2 /Pt, Bi 2 WO 6 /Pt). The enhanced photocatalysis benefited from the increased light harvesting owing to the excitation of both TiO 2 and Bi 2 WO 6 and the high quantum efficiency due to the heterojunction between Bi 2 WO 6 and TiO 2 and the Schottky junction between TiO 2 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 Bi 2 WO 6 /TiO 2 /Pt photocatalysis, and the hydroxyl radical derived from the reaction of holes and H 2 O was also responsible for pollutant degradation.