Defective Bi.333(Bi6S9)Br/Bi2S3 heterostructure nanorods: Boosting the activity for efficient visible-light photocatalytic Cr(VI) reduction

The design of a direct Z-scheme system heterostructure that can achieve an effective charge separation is highly desirable for photocatalysis. Herein, Bi.333(Bi6S9)Br/Bi2S3 heterostructure nanorods were synthesized by a facile hydrothermal method, and the photocatalytic reduction of Cr (VI) under visible light irradiation was conducted to evaluate their photocatalytic performance. Sulfur defects were introduced into the Bi.333(Bi6S9)Br/Bi2S3 hybrid nanorods in a controlled way during the phase evolution. Microstructural analysis shows that the interface of Bi.333(Bi6S9)Br/Bi2S3 heterostructure consists of (130) facet of Bi.333(Bi6S9)Br and (300) facet of Bi2S3. The high performance of the Bi.333(Bi6S9)Br/Bi2S3 hybrid nanorods was ascribed to sulfur defects and direct Z-scheme heterostructure. The sulfur defects can effectively adsorb and activate Cr (VI) while a direct Z-scheme mechanism between Bi.333(Bi6S9)Br and Bi2S3 significantly improved the separation and transfer efficiency of photogenerated electrons and holes. This work provides a new strategy for the design of advanced photocatalytic materials.