Synthesis and Structure of Nanocrystalline Copper Sulfides with Covelline and Djurleite Structures

Abstract

Nanocrystalline powders of copper sulfide with covelline and djurleite structure have been synthesized by chemical deposition from aqueous solutions of copper nitrate and sodium sulfide, as well as aqueous solutions of copper nitrate using thiourea as sulfiding agent in the presence of Trilon B as a stabilizer. Reaction of copper nitrate with sodium sulfide has been found to result in copper sulfide powders with the main phase showing the structure of hexagonal covelline with nanoparticle size of 3–6 nm. Moreover, the reaction produces monoclinic djurleite Cu_2–xS with particle size of ~70 nm and small non-stoichiometry in copper sublattice. Deposition from weakly alkaline aqueous solutions of copper nitrate, thiourea, and Trilon B on heating to ~90–100°C allowed preparation of monophase nanocrystalline CuS powders with particle size of 45–55 nm with structure of hexagonal covelline.