Template-free synthesis of ZnS nanocrystals with a new sulfur source and their photocatalytic study

•A facile, one-pot, template/capping agent-free route for preparation of ZnS NCs.•Powder X-ray diffraction measurements revealed the hexagonal structure of ZnS.•The ZnS NCs exhibit good photocatalytic activity for the degradation of MO dye.

A facile, one-pot, template-free solvothermal route for the synthesis of ZnS microspheres composed of nanocrystals (NCs) using 4,4′-dipyridyldisulfide (DPDS=(C5H4N)2S2) as a new in situ source of S2− ions without the use of capping agent has been presented. Powder X-ray diffraction measurements of the samples revealed the hexagonal structure of the ZnS NCs. FESEM and TEM analyses unveiled the spherical morphology of ZnS microspheres composed of NCs with diameter of 15–20 nm. Optical investigation showed that ZnS NCs have an UV–vis absorption at 250 nm which is blue-shifted compared to that of bulk ZnS and the calculated value of band gap is 4.6 eV. Photocatalytic investigation of the ZnS NCs showed very good photocatalytic activity for degradation of methyl orange (MO) dye.