0-Dimensional/1-dimensional S-scheme Ag2S/BiSI hetero-structured photocatalyst for superb Cr(VI) reduction under full spectrum irradiation.

Abstract

Developing ultraviolet (UV), visible (Vis) and near-infrared (NIR) responsive photocatalysts for Cr(VI) reduction is valuable. Herein, a 0-dimensional/1-dimensional (0D/1D) S-scheme Ag₂S/BiSI hetero-structured photocatalyst was successfully synthesized, which displays greatly enhanced Cr(VI) removal activity either under UV, Vis or NIR light irradiation. In-situ characterization technique and theoretical calculation confirm that an internal electric field (IEF), directing from Ag₂S to BiSI, exists between the interface, which facilitates the spatial-oriented separation of photoirradiated carriers. Furthermore, the immobilization of Cr₂O₇^2- and the transformation from *Cr₂O₇^2- to *CrO₃H₂ on the surface of S-scheme Ag₂S/BiSI heterostructure is much more favorable than that on the surface of single Ag₂S or BiSI. This work gives a comprehensive insight on the design of full spectrum responsive S-scheme photocatalysts for heavy metal removal.