Mediator-free direct dual-Z-scheme Bi2S3/BiVO4/MgIn2S4 composite photocatalysts with enhanced visible-light-driven performance towards carbamazepine degradation.

Mediator-free direct dual -Z- scheme Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 hybrid photocatalysts were controllably synthesized by a in-situ growth method for the first time. The as-constructed Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 composites displayed significantly improved photocatalytic activity for carbamazepine degradation by a factor of 44.9 and 423.1 compared to MgIn 2 S 4 and BiVO 4 , respectively. The mechanism for the enhanced activity was discussed deeply based on the experimental results. A deductive degradation pathway of CBZ was also proposed. • Mediator-free direct dual -Z- scheme Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 hybrid photocatalysts were synthesized. • The photocatalyst exhibited high performance for the degrdation of carbamazepine. • The rate constant improved by a factor of 44.9 and 423.1 compared to MgIn 2 S 4 and BiVO 4 , • A deductive degradation pathway of carbamazepine was proposed. The development of visible-light-driven photocatalysts with high photocatalytic performance is a desired research direction of scholars for energy crisis mitigation and environment restoration. In this study, a series of highly active mediator-free direct dual -Z- scheme Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 hybrid photocatalysts were controllably synthesized by a in-situ growth method for the first time. XRD manifested the coexistence of MgIn 2 S 4 , BiVO 4 and Bi 2 S 3 in the as-prepared nanocomposites. The intimate 2D-2D hetero-junction interfaces between BiVO 4 and MgIn 2 S 4 as well as BiVO 4 and Bi 2 S 3 in the hybrid photocatalysts were verified by TEM and HRTEM. The photocatalytic performance of as-fabricated catalysts was estimated by the degradation of carbamazepine (CBZ) under visible light illumination. The results demonstrated that the as-constructed Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 composites displayed significantly improved photocatalytic activity for CBZ degradation by factors of 44.9 and 423.1 compared to MgIn 2 S 4 and BiVO 4 , respectively. The enhanced photocatalytic performance of Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 composites was actually ascribed to the direct dual -Z- scheme migration mechanism, which was proved by XPS analysis, trapping experiments and ESR results. The formation of direct dual -Z- scheme efficiently enhanced the separation of charge carriers. Furthermore, according to DRS, the expanded light absorption in visible wavelength region also contributed to the boosted photocatalytic activity of Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 composites. The photocatalytic degradation products of CBZ were detected and a tentative degradation pathway was proposed. [ABSTRACT FROM AUTHOR]