Enhanced visible light photocatalytic activity of CeO2@Zn0.5Cd0.5S by facile Ce(IV)/Ce(III) cycle

In this study, CeO 2 @Zn 0.5 Cd 0.5 S heterostructure (Ce@ZCS) is synthesized via a simple two-step hydrothermal method. The effect of CeO 2 loading on the visible-light photoactivity of Zn 0.5 Cd 0.5 S is mainly investigated. It is found that Ce@ZCS shows a 1.9 times activity as high as ZCS for the MB degradation. The improved activity mainly results from the significant enhanced charge separation by CeO 2 , in which the electron transfer is obviously promoted by the facile Ce(IV)/Ce(III) cycle. The excited electrons of ZCS is easy to transfer to CeO 2 , thus obviously increasing the charge separation of ZCS. The accepted electrons by CeO 2 may easily be captured by the adsorbed O 2 to form O 2 − , and then O 2 − could combine with H + /H 2 O to form HO 2 , and OH. Finally, O 2 − , h + and OH are confirmed as the major oxidative species in photocatalytic reaction for Ce@ZCS, and a possible photocatalytic mechanism is proposed. The cheap, efficient Ce@ZCS photocatalyst could be applied for practical waste water treatment.