Formation of ZnS and CdS in the interlayer spaces of montmorillonite

Two types of semiconductor particles, ZnS and CdS, were formed in the interlayer spaces of montmorillonite by solid–solid reactions between Zn(II)- or Cd(II)-montmorillonite and Na2S at ambient temperature. The formation of the intercalation compounds was confirmed by powder XRD, TG–DTA and TG–MS. The in situ formation of ZnS and CdS nanoparticles in the interlayer spaces of montmorillonite was proved by UV–visible and photoluminescence spectroscopy. The diffuse reflectance absorption spectra of ZnS and CdS-montmorillonites exhibited the absorption onset at 345 and 541 nm, confirming the formation of ZnS and CdS nanoparticles in the interlayer spaces. The ZnS or CdS luminescence band at 583 nm for ZnS-montmorillonite or 529 nm for CdS-montmorillonite was weak due to the presence of quenching impurities in montmorillonite.

Graphical abstractThe intercalated ZnS or CdS single particles probably were disk- or plate-shaped particles with a thickness of ca. 0.3 nm and a diameter of ca. 2–7 nm for ZnS and ca. 6–10 nm for CdS where the disk or plate plane was oriented parallel to the silicate layer. The PL spectra of ZnS and CdS in montmorillonite showed the luminescence peaks at 583 and 529 nm, respectively. Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► The intercalated ZnS or CdS single particles probably were disk- or plate-shaped particles with a thickness of ca. 0.3 nm and a diameter of ca. 2–7 nm for ZnS and ca. 6–10 nm for CdS where the disk or plate plane was oriented parallel to the silicate layerIntercalated ZnS or CdS were plate-shaped particles oriented parallel to the silicate layer.► Raman bands of ZnS- and CdS-montmorillonite revealed the bands at 304, 604 cm-1 and at 304, 608 cm-1.► Absorption spectra of ZnS and CdS-montmorillonites exhibited the onset at 345 and 541 nm. PL spectra of ZnS and CdS in montmorillonite showed the emission peaks at 583 and 529 nm.Figure optionsDownload full-size imageDownload as PowerPoint slide