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

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)center dot 5H(2)O, 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.