Low temperature interface-mineralizing route to hollow CuS, CdS, and NiS spheres

Abstract

Submicrometer hollow CuS, CdS, and NiS spheres with diameters between 400 and 1300 nm were successfully prepared through an interface-mineralizing reaction in a NH₃·H₂O–CS₂ solution at low temperature. Several techniques were applied to characterize the interesting self-assembled structures. The compositions of the prepared CuS, CdS, and NiS materials were confirmed by X-ray powder diffraction (XRD), the surface atomic ratios and the valence state of ions were examined by X-ray photoelectron energy spectroscopy (XPS), and the morphologies of products by transmission electron microscope (TEM). The optical properties, including absorption and emission, were recorded by UV–vis absorption and fluorescence spectroscopy, respectively. In this approach, ethylenediamine (en) was substituted by aqueous ammonia (NH₃·H₂O) to avoid violent reactions with carbon disulfide (CS₂). The main advantage to this approach is that both ammonia and CS₂ played multi-functional roles in the assembly of hollow-sphere structures. The reaction sources themselves (CS₂) served as the reaction template and required no other templates to support it. The proposed interface-mineralizing mechanism is discussed, and the hollow-sphere structures obtained are envisioned to have applications in area of materials science.Key words: hollow-sphere structure, NH₃·H₂O–CS₂, metal sulfides