Preparation of self-assembled hollow microsphere CdS via solvothermal method and its optical properties

In this work, the hollow microsphere CdS has been prepared by solvothermal method with oxalic acid as auxiliary agent. The effects of different experimental conditions on the morphology of CdS have been investigated. The as-prepared CdS has been analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive spectrometer, room temperature photoluminescence and ultraviolet-visible (UV-Vis). And the photocatalytic activity has been investigated on the degradation of methylene blue under simulated solar light irradiation. XRD result indicates that hollow microsphere CdS is hexagonal phase, which is highly crystallized. FE-SEM results indicate that the diameter of hollow microsphere CdS is about 5 mu m, and the diameter of center hole is about 500 nm. UV-Vis result indicate that hollow microsphere CdS has a strong absorption in visible light region and the optical energy band gap is 2.31 eV. The fluorescence spectrum shows that hollow microsphere CdS structures have three emission peaks at 455, 545 and 582 nm, respectively. Photocatalytic result shows that the activity of hollow microsphere CdS remains 90 % after 5 recycle times, which indicates that hollow microsphere CdS has a good catalytic efficiency and stability to methylene blue. The growth mechanism of hollow microsphere CdS structures is also described.