Synthesis And Properties Of Iron Group Chalcogenides Nanostructures

Metal chalcogenides have attracted wide attentions due to their excellent physical and chemical properties. Among them, transition metal chalcogenides present promising applications in various fields such as photodetectors, photocatalysis and solar cells because of their unique optical, electronic, magnetic and superconductive properties. The thesis focuses on the preparation and characterizations of the Fe doped NiS nanorods and FeSe₂ microflowers assembled by nanosheets. The relevant results are shown as follows.（1） Fe-doped NiS ternary nanorods with uniform morphology have been successfully synthesized in ethylenediamine solvent by a solvothermal technique using Ni, S and FeCl₂·4H₂O as starting materials. The phase, morphology, compositions and microstructure of the products have been characterized by X-ray powder diffraction（XRD）, scanning electron microscopy（SEM）, energy dispersive X-ray spectroscopy（EDS） and transmission electron microscopy（TEM）. The optical properties of the sample have been studied. The results show that the Ni_1-xFe_xS nanorods are well crystallized single crystals and the highest Fe doping concentration x is about 17.51%. The addition of Fe²⁺ ions can facilitate the one-dimensional growth and enlarge the band gaps of the nanorods.（2） Three-dimensional FeSe₂ microflowers are synthesized by a facile solvothermal method using FeCl₂·4H₂O, selenium powder as raw materials and ethanolamine as solvent for the first time. The phase, morphology and compositions of the products have been characterized. The optical properties and catalytic activity for the hydrogen evolution reaction have been studied. The results show that FeSe₂ microflowers are comprised of nanosheets with the thickness about 50⁸0 nm. The optical band gap of the sample is determined to be 1.48 eV by UV-Visible absorption spectra. The catalytic activity for hydrogen evolution reaction is examined.The thesis reports the preparation and characterizations of Fe doped NiS nanorods and FeSe₂ microflowers assembled by nanosheets. These results would be helpful to the research of other metal chalcogenides with controlled properties.