Synthesis of CdS/BiOBr composite and its enhanced photocatalytic degradation for Rhodamine B

CdS/BiOBr composite photocatalysts were successfully prepared by a facile precipitation method and characterized by XRD, SEM, TEM, EDS, UV-vis and PI. The photocatalytic activities of the samples were evaluated by the degradation of Rhodamine B (RhB) under visible light irradiation. The effects of CdS content, catalyst dosage, and initial concentration of RhB solution on the photocatalytic degradation were investigated. The results indicated that the CdS/BiOBr composite photocatalysts exhibited strong absorption in the visible light region and possessed excellent photocatalytic activity and stability for RhB degradation. The 40%-loaded CdS/BiOBr composite photocatalyst was found to degrade 97% of RhB under visible light irradiation and showed no apparent decrease in activity after five cycles. The enhancement in both activity and stability were attributed to the enhanced light absorption and effective separation and transfer of photogenerated charges, originating from the well-matched overlapping band-structures and closely contacted interfaces. Experiments using radical scavengers indicated that center dot O-2(-) and h(+) were the main reactive species present in the photosystem. On the basis of the experimental results and estimated energy band positions, the mechanism for the enhanced photocatalytic activity was proposed. (C) 2014 Elsevier B.V. All rights reserved.