Visible-light-driven 3D hierarchical Bi2S3/BiOBr hybrid structure for superior photocatalytic Cr(VI) reduction

The most important approach to eliminate poisonous Cr(VI) from water utilizing visible-light photocatalytic activities is the reduction of highly toxic Cr(VI) to less harmful Cr(III). In this study, a facile one-pot homogenous precipitation method was designed for the first time to fabricate the heterojunction of Bi2S3/BiOBr. The hybrid structure was characterized using XRD, FE-SEM, EDS, TEM, UV–vis (DRS), XPS, and PL. The synthesized heterostructure confirmed the successful anchoring of Bi2S3 nanoparticles onto BiOBr nanosheets. The as-prepared Bi2S3/BiOBr hybrid structure exhibited significantly enhanced photocatalytic performance for the reduction of Cr(VI) to Cr(III) compared with pure BiOBr that confirmed by XPS analysis after 10 min. The hybrid structure of Bi2S3/BiOBr showed a superior rate constant 10 times higher than that for pure BiOBr. Moreover, the reduction efficiency of Cr(VI) solution containing 50 mg/L was improved up to 99.2% within 40 min by the addition of tartaric acid as a hole scavenger. The reduction efficiency of different photocatalysts towards Cr(VI) removal from the real sample was also examined. The Bi2S3/BiOBr hybrid structure can be reused after regeneration process without a significant loss in photoreaction behavior after four recycle runs.