Zn0@ZnS Core-Shell Nanoparticles via Oxidation of Intermediate Zn0 Nanoparticles

Zn0@ZnS core‐shell nanoparticles were prepared via reduction of ZnCl2 to Zn0 nanoparticles and subsequent partial oxidation with elemental sulfur. The intermediate, highly reactive Zn0 nanoparticles were obtained by sodium naphthalenide ([NaNaph]) reduction of ZnCl2 in tetrahydrofuran (THF). After centrifugation, the Zn0 nanoparticles were redispersed in a solution of sulfur in toluene and oxidized by subsequent heating to reflux. According to electron microscopy (HRTEM, HAADF‐STEM), the Zn0@ZnS core‐shell nanoparticles exhibit a mean outer diameter of 12 ± 4 nm, consisting of an inner Zn0 core (8 nm in diameter) and a ZnS shell (2 nm in diameter). HRTEM and XRD confirm the crystallinity of both core and shell. The Zn0@ZnS nanostructure shows synergistic properties of core and shell: the ZnS layer efficiently passivates the reactive Zn0 metal core against oxidation, whereas the optical properties point to dominating metallic behavior of the Zn0 metal core despite of the ZnS shell.