Hydrothermal synthesis and optical property of ZnS/CdS composites

ZnS/CdS semiconductor composites were synthesized successfully by combining a hydrothermal route with a homogeneous precipitation process. The as-prepared products were characterized by x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectrometer. The results showed that the as-prepared products were composed of ZnS microspheres with a face-centered cubic phase and CdS nanoparticles with hexagonal phase, CdS nanoparticles were found to be assembled on the surfaces of the cubic ZnS microspheres. In addition, the ultraviolet-visible absorption spectroscopy and the room temperature photoluminescence (PL) spectroscopy of the ZnS microspheres and ZnS/CdS composites were also investigated. The PL testing indicated that the emission peak of as-prepared ZnS/CdS composites not only exhibited an obvious blue shift but also its intensity had a large enhancement compared to the pure ZnS microspheres. Furthermore, the photocatalytic degradation test showed that the as-prepared ZnS/CdS composites showed excellent photocatalytic degradation activity for methyl orange under UV irradiation. This enhanced activity may be related to the modification of CdS nanoparticles on the surfaces of ZnS microspheres.