Photocatalytic Activity Enhancement for Bi2WO6 by Fluorine Substitution

F- substituted Bi2WO6 (Bi2WO6-XF2X) photocatalysts with high activity have been successfully synthesized by a two-step process. The effects of F- substitution oil the crystal structure and photocatalytic activity of Bi2WO6 were investigated. F- substitution could change the original coordination around the W and Bi atoms. Comparing with Bi2WO6, the photocatalytic activity of Bi2WO6-XF2X increased about 2 times for degradation of MB under visible-light (lambda > 420 nm) irradiation. Density functional calculations revealed that Bi2WO6-XF2X has a wider valence bandwidth and lower valence band position. The high activities of Bi2WO6-XF2X photocatalysts come from its valence band which increase the mobility of photoexcited charge carriers and possess a stronger oxidation power.