Intensive photocatalytic activity enhancement of Bi5O7I via coupling with band structure and content adjustable BiOBrxI1−x

Abstract

Band structure and component content are the key factors for determining the activity of semiconductor heterojunction. In this study, a novel Bi5O7I/BiOBrxI1−x heterostructure was synthesized by a simple hydrobromic (HBr) acid etching method through transforming partial of Bi5O7I to I− ion doped BiOBr (BiOBrxI1−x) at room temperature without adding extra dopant. Both the band structure and component content of Bi5O7I/BiOBrxI1−x alter with the additive HBr acid. The Bi5O7I/BiOBrxI1−x (S3.0) sample exhibits the best photocatalytic activity, 6 times higher than that of pure Bi5O7I, for the degradation of methyl orange under visible-light (λ > 420 nm). The activity enhancement of Bi5O7I/BiOBrxI1−x is primarily ascribed to the improved separation efficiency of photocharges, originated from the adjustable band structure and component content. The significant findings of this paper provide a facile way to construct highly efficient semiconductor heterojunction via playing the synergetic effect of adjustable band structure and component content for purifying organic pollutants in wastewater.