Construction of Core-shell Sb2s3@Cds Nanorod with Enhanced Heterointerface Interaction for Chromium-Containing Wastewater Treatment

How to collaboratively reduce Cr(VI) and break Cr(III) complexes is a technical challenge to solve chromium-containing wastewater (CCW) pollution. Solar photovoltaic (SPV) technology based on semiconductor materials is a potential strategy to solve this issue. Sb2S3 is a typical semiconductor material with total visible-light harvesting capacity, but its large-sized structure highly aggravates disordered photoexciton migration, accelerating the recombination kinetics and resulting low-efficient photon utilization. Herein, the uniform mesoporous CdS shell is in situ formed on the surface of Sb2S3 nanorods (NRs) to construct the core-shell Sb2S3@CdS heterojunction with high BET surface area and excellent near-infrared light harvesting capacity via a surface cationic displacement strategy, and density functional theory thermodynamically explains the breaking of Sb-S bonds and formation of Cd-S bonds according to the bond energy calculation. The Sb-S-Cd bonding interaction and van der Waals force significantly enhance the stability and synergy of Sb2S3/CdS heterointerface throughout the entire surface of Sb2S3 NRs, promoting the Sb2S3-to-CdS electron transfer due to the formation of built-in electric field. Therefore, the optimized Sb2S3@CdS catalyst achieves highly enhanced simulated sunlight-driven Cr(VI) reduction (0.154 min(-1)) and decomplexation of complexed Cr(III) in weakly acidic condition, resulting effective CCW treatment under co-action of photoexcited electrons and active radicals. This study provides a high-performance heterostructured catalyst for effective CCW treatment by SPV technology.