Solid-CdS and hollow-ZnS porous submicrospheres: Direct preparation by C-S decomposition of thiol via solvothermal processing

Porous solid-CdS or hollow-ZnS submicrospheres (SMSs) were prepared by reaction of 2-mercaptoethanol as S-source with Cd2+ or Zn2+ in ethanol using solvothermal route. Without any alkaline, solid-CdS SMSs with an average diameter of 440 nm were obtained and their size distribution in the range of 390-490 nm is above 80%; With the addition of alkaline, single crystal CdS nanorods with high-temperature-stable hexagonal phase were synthesized. With or without poly(N-vinyl-2-pyrrolidone) (PVP), solid-CdS SMSs can be prepared, but the addition of the PVP leads to the preparation of relative uniform CdS-SMSs. Hollow-ZnS SMSs with an average diameter of 340 nm were obtained under the existence of alkaline. The longer reaction time hardly influences on the size of the hollow-ZnS SMSs. More or less amount of alkaline directly influences the morphology of final product. Close-ring-shaped ZnS was prepared under the existence of less alkaline. With or without PVP under preparation reaction, hollow-ZnS SMSs can also be synthesized. Thus, during preparation of either CdS or ZnS, the PVP function is not as template, but as surfactant. The BET measurement results show that the special surface areas of solid-CdS and hollow-ZnS SMSs are 25.56 and 83.55 m2/g, respectively. The adsorption of methylene blue shows that the hollow-ZnS SMSs have very strong adsorption and decomposition ability.