Facile ion-exchange synthesis of urchin-shaped CdS/Bi2S3 heterostructures with enhanced photostability and visible light photocatalytic activity

Abstract

Blackberry-like CdS microspheres were synthesized by a facile hydrothermal method. Subsequently, through a simple ion-exchange reaction between the CdS microsphere and Bi(NO₃)₃·5H₂O, novel urchin-shaped CdS/Bi₂S₃ core/shell heterostructures have successfully been fabricated. The photocatalytic activity and photostability were evaluated by degradation of rhodamine B (RhB) under visible light irradiation. The results show that the content of Bi₂S₃ had important effects on the photocatalytic activity, and the CdS/Bi₂S₃ heterostructures with the theoretical molar ratio of Bi/Cd 0.25 exhibited the best photocatalytic activity. The improved photocatalytic activity and photostability were attributed to the visible light absorption enhanced by Bi₂S₃ and the formation of a heterojunction between CdS and Bi₂S₃, which can effectively accelerate the charge separation and transfer corrosive holes from CdS to robust Bi₂S₃. Experimentally and theoretically, Bi₂S₃ anchored on CdS acts as a corrosion protection agent for CdS and also acts as a co-catalyst.