| Nano transition metal sulfide is widely used in photoelectron catalysis, super capacitor, lithium ion battery, catalytic desulfurization and waste water treatment due to its unique physical and chemical properties. In this paper, the nickel sulfide (NiS),the porous MoS2 and the composite foam of molybdenum disulfide/carbon nanotubes(MoS2/CNTs) were prepared by some new synthetic methods. Their formation mechanism and electrochemical properties were studied, and the application of porous MoS2 in the treatment of dye wastewater was also explored. The detailed research contents are summarized as follows.1. The NiS nanocrystals were prepared by the method of hot-bubbling in solvothermal system of the octadecylene using the acetyl acetone nickel as nickel source and hydrogen sulfide as sulfur source. The morphology, size and structure of NiS nanocrystals were characterized by the Scanning electron microscopy (SEM),X-ray powder diffraction (XRD), transmission electron microscopy and energy dispersive spectroscopy (TEM-EDX). At the same time,the NiS nanocrystals were modified on the surface of glassy carbon electrode, and the electrochemical performance were characterized by using linear sweep voltammetry, cyclic voltammetry, electrochemical impedance spectroscopy technology under acidic conditions. The results showed that the NiS nanocrystals prepared by hot-bubbling method have not only high crystallinity, but also excellent electrocatalytic activity for hydrogen evolution reaction in the 0.5 M H2SO4 electrolyte solution.2. The composite foam of MoS2/CNTs was prepared by impregnation,supercritical carbon dioxide drying and calcination using the hybrid of phenol-formaldehyde polymer,carbon nanotube and (NH4)2MoS4 as precursor. The composite material has the advantages of sTab structure, high elasticity and lithium intercalation/de intercalation process, which can keep the excellent properties in a certain range. In addition,the composite foam has also the advantages of strong electrical conductivity, large specific surface area. The pore size distribution is from nanometer to micrometer, which makes them as an ideal cathode material for lithium ion batteries (LIB). By studying the electrochemical performance of lithium ion batteries, we found that this sponge-like structure of the composite is conducive to Li/Li+ transport. It not only accelerates the diffusion rate of lithium ion, but also expands the storage capacity of Li+ After the charging/discharging cycles from 1 C to 10 C, the specific capacity of 870 mA · h · g－1 can be achieved up to 100 cycles at the current of 1 C, which means the 93.0% capacity can be recovered, which indicates that the composite foam has high capacity and good stability3. The fibrous porous MoS2 was synthesized using fibrous poly ammonium molybdate sodium as molybdenum source, and using thiourea as sulfur source. The results of XRD and TEM showed that all the samples are nano materials of MoS2, but they have different morphology in different synthesis conditions. The new synthesis method, i.e., the hydrothermal-vapor phase sulfuration can keep the microstructure of the precursor, so the samples of porous MoS2 nanomaterials were prepared, while using the common hydrothermal sulfuration, we only obtained the flower shaped MoS2 nanosheets. The surface activity of porous MoS2 was evaluated by adsorption of methyl orange in the aqueous solution. By comparison, we found that the porous MoS2 presents better adsorption properties of methyl orange than the MoS2 nanosheets, and also the methyl orange can also be desorbed easily. This is mainly attributed to its special adsorption properties and the huge specific surface. |
