Phase transition in ZnS nanoparticles: electrical, thermal, structural, optical, morphological, antibacterial and photocatalytic properties

Zinc Sulphide nanoparticles (ZnS-NPs) are synthesized by microwave assisted chemical precipitation method. The as-synthesized nanoparticles are identified by X ray diffraction and electrical studies to examine the structural transition. The HT-XRD at 1000 C (373 K) and 2000 C (473 K) of ZnS-NPs also confirms structural transition of cubic to hexagonal phase. Thermal properties of the ZnS sample is also studied using thermo gravimetricdifferential thermal analysis (TG-DTA). From D.C. electrical resistance, a discontinuity occurs in the temperature resistance curve of the ZnS-NPs due to phase transition around 450 K. The energy dispersed x-ray analysis and Raman spectra of the ZnS-NPs confirm the presence of zinc and sulphur. The optical studies of the prepared ZnS-NPs are confirmed by its UV-vis and PL spectra. The TEM image of cubic ZnS-NPs reveals the well distribution of spherical shaped particles with mean size of 12.52 nm with standard deviation of 9.326 nm. According to the photocatalytic results of ZnS-NPs for the degradation of methylene blue (MB) have the highest degradation efficiency of 93.24% under UV irradiation within 80 min. Antibacterial effects of ZnS-NPs nanoparticles against some pathogens, like gram-negative, gram-positive, E. coli (Escherichia coli), S. aureus (Staphylococcus aureus) bacteria.