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.