Enhanced photoluminescence and photocatalytic activity of Ca2+ addition into ZnS nanoparticles synthesized by hydrothermal method

A surfactant-free hydrothermal technique was used to synthesize calcium (Ca2+) incorporated ZnS nanoparticles (ZnS:Ca). The structural, morphological, optical and microstructural properties of the produced nanoparticles are investigated by XRD, SEM, PL and XRF techniques, respectively. The XRD patterns revealed the preservation of the cubic phase after Ca2+ addition, and a decrease of the crystallite size. The SEM micrographs showed the formation of good shaped spherical particles, and evenly distributed. The ZnS:Ca photoluminescence emission bands were blue-shifted and broader than those of pristine ZnS. Finally, the photocatalytic activity of methylene orange (MO) was enhanced by Ca2+ incorporation. According to XRF measurements, the solubility limit of Ca2+ in ZnS lattice is found to be at 0.16% of Ca2+/Zn2+ mass ratio. This result can explain the saturation of the rate constant in the photocatalysis process.

Automated summary

In this study, a surfactant-free hydrothermal technique was used to synthesize calcium incorporated zinc sulfide nanoparticles. The structural, morphological, optical and microstructural properties of the nanoparticles were investigated using various techniques. The results showed that the addition of calcium preserved the cubic phase and reduced the crystallite size. The calcium incorporation also resulted in the formation of well-shaped spherical particles with even distribution. Furthermore, the photoluminescence emission bands of the calcium incorporated zinc sulfide nanoparticles exhibited a blue-shift and broader width compared to pristine zinc sulfide, and the photocatalytic activity was enhanced.