Synthesis of Metal Sulfides from a Deep Eutectic Solvent Precursor (DESP)

Recently, deep eutectic solvents (DESs) have received great interest as sustainable reaction media for nanoscale and functional materials. We report on a new choline chloride (ChCl) and thioacetamide (TAA) based DES for the synthesis of a series of binary metal sulfides including Sb2S3, Bi2S3, PbS, CuS, Ag2S, ZnS, and CdS. In these reactions, the ChCl/TAA based DES serves as all-in-one reactant, solvent, and template or deep eutectic solvent precursor (DESP). The reaction is supposed to proceed in two steps. A metal-DES complex is first generated by adding the respective metal salts to the DES solution at a relatively low temperature. Then the metal-DES complex decomposes to form the final metal sulfides products upon heating. This method provides a simple reaction system and a general strategy to synthesize metal sulfides. Some unique shaped products, such as Sb2S3 plates agglomerated by rod-like particles, hexagonal CuS single crystals, and three-dimensional hierarchical ZnS microspheres, are obtained via this method and the sizes and shapes of obtained samples can to some extent be controlled by temperature or reactant concentrations.