Synthesis mechanism, enhanced visible-light-photocatalytic properties, and photogenerated hydroxyl radicals of PS@CdS core-shell nanohybrids

In this study, spherical polystyrene (PS)@CdS core-shell structure nanoparticles (CSNPs) were prepared by sonochemical method. The influences of the surfactant PVP, the order of adding precursors, the molar ratio of S/Cd, and the reaction time on structure were carefully studied. Results of SEM, TEM, EDS, XRD, and FT-IR showed that the as-prepared nanohybrids have a typical core-shell structure with 260 nm core and a uniform shell with thickness ranging from 10 to 30 nm, both PVP and the order of adding precursors were the controlling parameters. In addition, the as-synthesized PS@CdS CSNPs exhibited much higher photocatalytic activity for RhB under visible light irradiation compared with pure CdS, which should be attributed to their synergic effect between core and shell, amount of hydroxyl groups on the surface, good monodispersity, and so on. Besides, the production of photogenerated hydroxyl radical ((OH)-O-center dot) was in accordance with the RhB decolorization efficiency from the prepared PS@CdS CSNPs. It indicated that (OH)-O-center dot was the main active oxygen species in the photocatalytic process.