CdS, TiO2 and Pd° nanoparticles growing in the interlamellar space of montmorillonite in binary liquids

The interfacial layers on the clay mineral/liquid interface usually range from 0.5 to 5 nm. When clay mineral particles are dispersed in binary mixtures (ethanol–cyclohexane and ethanol–toluene), an adsorption layer evolves on their surface which may function as a nanophase reactor for the synthesis of nanocrystalline materials. In the adsorption layer on the surface of montmorillonite CdS, TiO2 and metallic palladium nanoparticles with a diameter of 5–15 nm were grown. The appearance of semiconductor particles and the dependence of particle size upon the Cd2+ precursor concentration were followed by determination of the band gap energy. The rheological characteristics of suspensions containing nanoparticles are basically different from those of the original suspension. Solid powder samples obtained from the suspensions were studied by small-angle X-ray scattering (SAXS) measurements; the size of nanoparticles located on the clay mineral surfaces was determined and changes in the structure of the support were monitored.