Synthetic phase and morphology control over colloidal nickel sulfide nanocrystals

Joint Event on 15^th International Conference and Exhibition on Materials Science and Engineering & 3^rd International Conference on Applied Crystallography

November 07-08, 2018 | Atlanta, USA

Gozde Barim

University of Southern California, USA

Posters & Accepted Abstracts: Res. Rev. J Mat. Sci

DOI: 10.4172/2321-6212-C8-036

Abstract

Binary nickel sulfides exist in a variety of phases and stoichiometries, including NiS2, Ni3S4, �±-NiS, �²-NiS, Ni9S8, Ni7S6 and Ni3S2. Distinct phases of the binary nickel sulfide system have potential to be used as bifunctional catalysts for water splitting, cathode materials for lithium-ion batteries, absorber layers for solar cells, hydrodesulfurization catalysts, or supercapacitors. However, the complicated nature of the Niâ��S phase diagram makes the solution synthesis of phase-pure colloidal nanocrystals challenging. In this presentation, the phase- and morphology-controlled solution synthesis of colloidal nickel sulfide nanocrystals is demonstrated. Nanocrystals of Ni3S4, �±-NiS, �²-NiS, Ni9S8 and Ni3S2 can be independently prepared by tuning key synthetic parameters of S:Ni precursor ratio, capping ligand, reaction time and temperature. S:Ni ratio and temperature influences the phase of nanocrystals, a phase transformation from cubic Ni3S4 to hexagonal �±-NiS and then rhombohedral �²-NiS with increasing S:Ni ratios and temperature is observed. 1-dodecanethiol is shown as an important phase and shape-directing agent. In the presence of 1-dodecanethiol, Ni9S8 nanocrystals with quasi-spherical morphology or Ni3S2 nanoparticles with a multi-pod like morphology can be obtained by using various disubstituted thioureas are sulfur precursors.

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