Synthesis of capped Cr-doped ZnS nanoparticles with improved bactericidal and catalytic properties to treat polluted water

Inorganic semiconducting ZnS doped with Cr nanoparticles was fabricated using chemical co-precipitation method with monothioethylene glycol as capping agent. This study is an effort to investigate as to how various concentration ratios of systematically doped Cr (1, 3, 5, and 7 wt%) to ZnS affect structural, optical, and morphological properties at room temperature. Powder X-ray diffraction (XRD) studies revealed that crystallinity improved upon doping and the synthesized material has cubic structure without secondary phase. XRD and Raman spectra showed successful incorporation of Cr³⁺ particles into ZnS host lattice. The functional groups and chemical species associated with vibration of molecules were determined with Fourier transform infrared spectroscopy (FTIR). Field-emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscope (HR-TEM) images showed nanoscale particles with cubic and spherical morphology. Elemental composition of Cr-ZnS particles was determined using energy-dispersive X-ray (EDX) spectroscopy. Kinetics of degradation of methylene blue (MB) catalyzed via synthesized nanoparticles was recorded under UV–Vis irradiation. The antimicrobial evaluation of Cr-doped ZnS nanocomposites against MDR S. aureus showed significant (p < 0.05) inhibition zones compared to undoped ZnS. The catalytic activity results indicate that ZnS is an efficient nanocatalyst that could be effectively used for the removal of environmental pollutants.