Facile synthesis of ZnS nanostructured spheres and their photocatalytic properties

Hexagonal ZnS nanostructured spheres self-assembled from ZnS nanocrystals had been synthesized at a low temperature of 100 degrees 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 TiO2 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. (C) 2009 Elsevier B.V. All rights reserved.