Influence of Ce3+ doping on the optical and photocatalytic properties of Zn0.8 Cd0.2S-ethylenediamine hybrid nanosheets

Abstract

The Ce3+-doped Zn0.8Cd0.2S-ethylenediamine (En) hybrid nanosheets were successfully synthesized by a simple solvothermal method and characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), UV–vis diffusion reflectance spectroscopy (UV–vis DRS) and room-temperature photoluminescence spectra (PL). The effects of Ce3+ doping amount on the photo-absorption properties and photocatalytic H2 evolution rates under visible light irradiation over Zn0.8Cd0.2S-En hybrid nanosheets were also investigated. The results show that the incorporation of Ce3+, existing in the form of Ce2S3 with uniformly distribution in sample can narrow the band gap, enhance the photo-absorption and extend the photo-absorption range of the Zn0.8Cd0.2S-En hybrid nanosheets. The photocatalytic activity tests prove that Ce3+-doped Zn0.8Cd0.2S-En nanosheets have much higher photocatalytic hydrogen production activity when compared with the undoped one. Under the irradiation of visible light, the highest photocatalytic hydrogen production rate of 229.2 μmol h−1 is observed over 0.1 wt.% Ce3+-doped Zn0.8Cd0.2S-En nanosheets, which is about 1.4 times higher than that of the undoped Zn0.8Cd0.2S-En nanosheets. The improved photocatalytic activity of Ce-doped samples ascribes to the enhanced photo-response in the visible light region and the efficient separation of electron-hole pairs due to the formation of heterojunction between Zn0.8Cd0.2S-En and Ce2S3.