Facile synthesis of ZnS nanostructured spheres and their photocatalytic properties

Abstract

Hexagonal ZnS nanostructured spheres self-assembled from ZnS nanocrystals had been synthesized at a low temperature of 100 °C by using l-cysteine (an ordinary amino acid) as a sulfur source and gelatin (an ordinary amino acid) as the assembling agent. The reaction time, l-cysteine and gelatin all played key roles in the formation of ZnS spheres. By combining the results of X-ray diffraction (XRD), transmission electron microscope (TEM), field-emission scanning electron microscopy (FESEM), ultraviolet–visible (UV–vis) absorption and photoluminescence (PL) spectra, a structural and morphological characterization of the products was performed. The photocatalytic activity of ZnS spheres had been tested by degradation of Rhodamine-B (RB) under UV light compared to commercial Degussa P-25 TiO 2 and that of ZnS prepared without gelatin or with other sulfur source, indicating that ZnS spheres synthesized by using l-cysteine and gelatin exhibit enhanced photocatalytic activity for degradation of RB.