CdSe/ZnS core-shell quantum dots (QDs) were prepared using combination of microwave irradiation and photochemical synthesis of sulfur based material. Versatile analyses of X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), Transmission electron microscopy (TEM), Photoluminescence (PL) and UV-Visible (UV-Vis) spectroscopy were employed to verify the formation of core-shell structure at nanoscale. Due to the growth of ZnS as shell, trap state emission of CdSe cores quenched significantly and the fundamental band gap emission of CdSe QDs with FWHM of above 36 nm was clarified as an evidence of the formation of core-shell structure. Moreover, the results revealed that CdSe/ZnS QDsshow superior photocatalytic activity rather than CdSe QDs for photo-degradation of Methyl orange (MO). (C) 2017 Elsevier B.V. All rights reserved.