Department of Chemistry

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https://repository.udsm.ac.tz/handle/123456789/82

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Browsing Department of Chemistry by Author "Khan, Malik D"

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    Synthesis and characterization of PbS nanoparticles in an ionic liquid using single and dual source precursors
    (Materials Science and Engineering: B, 2018) Tshemese, Zikhona; Khan, Malik D; Mlowe, Sixberth; Revaprasadu, Neerish
    We report a green route for the synthesis of PbS nanoparticles in an imidazolium based ionic liquid (IL) (1-ethyl-3-methylimidazolium methanesulfonate) using single source and dual source precursor methods. Lead ethyl xanthogenate complex was used as single source molecular precursor for the synthesis of PbS nanoparticles, whereas in dual source approach organic sulfur (1-dodecanethiol) and inorganic sulfur (sodium sulfide) sources were used to observe the suitability of different sulfur sources on formation of PbS nanoparticles. The results showed that the temperature has an effect on the as prepared nanoparticles for both routes. X-ray diffraction (XRD) studies confirmed formation of cubic phase of PbS from both routes. Electron microscopy techniques showed that the nanoparticle morphologies differed significantly depending on the synthetic factors such as temperature, nature of precursors and ranged from spherical to cubic shapes.
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    Tailoring Shape and Crystallographic Phase of Copper Sulfide Nanostructures Using Novel Thiourea Complexes as Single Source Precursors
    (Journal of Inorganic and Organometallic Polymers and Materials, 2019-05) Ketchemen, Kevin IY; Khan, Malik D; Mlowe, Sixberth; Nyamen, Linda D; Ndifon, Peter T; O'Brien, Paul; Revaprasadu, Neerish
    Copper sulfide thin films and nanoparticles have been prepared via aerosol assisted chemical vapour deposition and solvothermal hot injection routes, respectively. Both routes employed heterocyclic amine based benzoylthioureato-copper(II) complexes as single source precursors. Copper sulfide thin films of diverse morphologies ranging from cubic to snowy or irregular crystallites depending on the deposition temperature were observed. Powder X-ray diffraction studies of the as deposited thin films have indicated the formation of hexagonal and cubic phases of copper sulfide. In the case of the nanoparticles, Roxbyite (Cu1.75S) phase was obtained in dodecanethiol at temperatures of 150, 190 and 230 °C. However, a preferred growth of nanoparticles was observed in the presence of oleylamine whereas the roxbyite phase was obtained at temperatures of 150, 200 and 250 °C. Also transmission electron microscopy showed the formation of close to spherical, hexagonal nano-disk and rod shaped nanoparticles.