Preparation, Characterization And Property Of Nickel Phosphide And Its Composite

Nickel phosphides are currently of great scientific interest in materials science due to their superior performance in electrical, magnetic, optical and catalytic properties. Especially, as a new type of catalytic materials, nickel phosphide is a new high-efficiency catalyst for the hydrodesulfurization(HDS), and hydrodenitrogenation(HDN), and a potential photocatalyst for the treatment of waste water. In order to improve the performance of nickel phosphides significantly, small changes of the material structure may lead great changes to the properties of the materials by controlling the morphology and size. In this paper, taking nickel phosphide as the main research object, nickel phosphide and its composities were successfully designed and prepared, and the growth mechanism and performances were also discussed. The main contents are summarized as follows:1. Dendritic Ni2 P microstructures were successfully synthesized via an EDTA-mediated hydrothermal route, using nickel sulfate and white phosphorus as a starting material. X-ray powder diffraction, energy dispersive X-ray spectrometer analysis, and Field-emission scanning electron microscopy were used to characterize the as-obtained products. The results showed that the as-prepared product had a hexagonal phase and was composed of a large quantity of well-defined dendrites which have the secondary branch-like structure. Further study shows that the morphology of the as-obtained Ni2 P microstructures was highly dependent on the amount of ethylenediamine tetraacetic acid, the reaction temperature, and the reaction time. Then based on some captured intermediates, a possible growth mechanism of the as-obtained Ni2 P dendrites was proposed. Furthermore, UV-Vis absorption spectroscopy of the product was discussed.2. Ni12P5 hollow microspheres were successfully synthesized by a facile mixed CTAB/SDS surfactant assisted hydrothermal route, using nickel chloride and white phosphorus as raw materials. The phases and morphologies of the products were characterized by means of X-ray powder diffraction(XRD), field emission scanning electron microscopy(FE-SEM) and transmission electron microscopy(TEM). It was interesting to found that CTAB/SDS could form a micro-reactor by the mixed micelles in the aqueous solution, which serves as a soft template for Ni12P5 hollow microspheres. Furthermore, research also showed that the as-prepared Ni12P5 hollow microspheres exhibited a good photocatalytic degradation activity for some organic dyes(such as Rhodamine B(Rh B), Methylene Blue(MB), Pyronine B, and Safranine T), and the degradation ratio could achieve more than 80%.3. Flower-like Pb S/Ni2 P composite was synthesized by combining solvthermal route with hytrothermal process. The composites were characterized by x-ray diffraction(XRD), field-emission scanning electron microscopy(FE-SEM) and transmission electron microscopy(TEM). The results showed that the as-obtained composite was composed of the cubic Pb S flowers and hexagonal Ni2 P nanoparticles, and Ni2 P nanoparticles coated on the surfaces of flower-like Pb S microstructures. Furthermore, the photocatalytic activity of the obtained samples was evaluated by the photocatalytic degradation of a model organic pollutant, Methylene Blue(MB) under visible light irradiation. The results indicated that the as-prepared composites showed enhanced photocatalytic degradation activity for Methylene Blue.4. Ni2P/Fe S composite with core-shell structure was synthesized by a facile two-step chemical route. The composites were characterized by x-ray diffraction(XRD), field-emission scanning electron microscopy(FE-SEM) and transmission electron microscopy(TEM). The results showed that the as-obtained composite was composed of hexagonal Ni2 P and hexagonal Fe S nanosheets, and Fe S nanosheets grew on the outside surface of Ni2 P hollow microspheres. Furthermore, the as-obtained Ni2P/Fe S composite also exhibited superior absorption activity for some organic dyes(Safranine T, Methylene blue(MB), Methyl orange(MO) and Pyronine B(PB)), when compared to the individual Ni2 P, which may be used in the environmental issues.