Photocatalytic activity of Bi2W06/Bi2S3 heterojunctions: the facilitation of exposed facets of Bi2W06 substrate

Bi2S3/Bi(2)W0(6) hybrid architectures with exposed (020) Bi(2)W0(6) facets have been synthesized via a controlled anion exchange approach. X-ray photoelectron spectroscopy (XPS) reveals that a small amount of Bi2S3 was formed on the surface of Bi(2)W0(6) during the anion exchange process, thus leading to the transformation from the Bi(2)W0(6) to Bi2S3/Bi(2)W0(6). A rhodamine B (RhB) aqueous solution was chosen as model organic pollutants to evaluate the photocatalytic activities of the Bi2S3/Bi(2)W0(6) catalysts. Under visible light irradiation, the Bi2S3/Bi(2)W0(6)-TAA displayed the excellent visible light photoactivities compared with pure Bi2S3, Bi(2)W0(6) and other composite photocatalysts. The efficient photocatalytic activity of the Bi2S3/Bi(2)W0(6)-TAA composite microspheres was ascribed to the constructed heterojunctions and the inner electric field caused by the exposed (020) Bi(2)W0(6) facets. Active species trapping experiments revealed that h(+) and 0(2)(center dot-) are the main active species in the photocatalytic process. Furthermore, the as-obtained photocatalysts showed good photocatalytic activity after four recycles. The results presented in this study provide a new concept for the rational design and development of highly efficient photocatalysts. (C) 2016 Elsevier B.V. All rights reserved.