Growth and characterization of NiS and NiCoS nanoparticles in mordenite zeolite host

We report the optical and structural properties of NiS and the ternary NiCoS nanoparticles in mordenite zeolite. The samples were obtained by sulfidation of the Ni(2+) and Co(2+) ion-exchange zeolite in a Na(2)S solution at room temperature. The optical properties of the samples were studied by UV-visible spectroscopy. Their crystalline structure and morphology were studied by XRD and scanning electron microscopy. The results show that the nanoparticles are inside the zeolite channels and cavity. Exciton absorption peaks at higher energy than the fundamental absorption edge of bulk NiS and CoS indicate quantum confinement effects in nanoparticles as a consequence of their small size. The absorption spectra show that the optical band gap varies in the range 3.53-3.9 eV, depending on the semiconductor material and their relative concentration. (C) 2006 Elsevier B.V. All rights reserved.