Ultrasonication-Assisted Synthesis of ZnxCd1−xS for Enhanced Visible-Light Photocatalytic Activity

Lei Yang,Longfeng Li,Xianliang Fu,Mingzhu Liu,You Fan,Haijie Ben,Shifu Chen,Maolin Zhang

doi:10.3390/catal10030276

Abstract

ZnxCd1−xS as a solid solution photocatalyst has attracted widespread attention for its unique adjustable band gap structure and good and stable performance. A novel synthesis approach for ZnxCd1−xS is still required to further improve its performance. In this study, we synthesized a series of ZnxCd1−xS (x = 0−1) solid solutions via an ultrasonication-assisted hydrothermal route. In comparison with conventional methods of preparation, the sample prepared by our innovative method showed enhanced photocatalytic activity for the degradation of a methyl orange (MO) solution under visible light due to its high crystallinity and small crystallite size. Furthermore, the composition and bandgap of ZnxCd1−xS can be tuned by adjusting the mole ratio of Zn2+/Cd2+. Zn0.3Cd0.7S shows the highest level of activity and stability for the degradation of MO with k = 0.85 h−1, which is 2.2 times higher than that of CdS. The balance between band gap structure-directed redox capacity and light absorption of Zn0.3Cd0.7S accounts for its high photocatalytic performance, both of which are determined by the composition of the solid solution. Also, a degradation mechanism of MO over the sample is tentatively proposed. This study demonstrates a new strategy to synthesize highly efficient sulfide photocatalysts.

Highlights

Organic dyes discharged from the synthetic textile industry and other industrial processes are one of the largest groups of pollutants released into aquatic environments [1,2]
The crystal structure and the average crystallite size of the prepared xZCS samples were analyzed by X-ray diffraction (XRD)
The gradual phase transition is thermodynamically favored by the fact that the zinc blende structure is more stable than wurtzite, whereas the wurtzite phase is more stable for CdS [20]

Summary

Introduction

Organic dyes discharged from the synthetic textile industry and other industrial processes are one of the largest groups of pollutants released into aquatic environments [1,2]. The removal of these dyes is vital for the protection and purification of water, and for the maintenance of human and ecological health. Almost 200 visible-light photocatalysts have been developed for the abatement of environmental pollutants and the extraction of H2 from water [4,5,6,7,8,9]. Improving the stability of CdS emerges as a key issue for the application of CdS-based photocatalysis

Methods

Results

Conclusion