Very slow formation of copper sulfide and cobalt sulfide nanoparticles in montmorillonite

Intercalation of semiconductor nanoparticles, copper sulfide or cobalt sulfide, into montmorillonite was carried out by solid-solid reactions of Cu(II)- or Co(II)-montmorillonite with sodium sulfide at room temperature. The intercalation compounds were characterized by X-ray diffraction, thermal analysis, transmission electron microscopy, Raman, UV-visible and photoluminescence spectroscopy. The photoluminescent copper sulfide and cobalt sulfide nanoparticles in the interlayer spaces formed after the sample storage at room temperature for several months.