Synthesis, Characterization And Properties Of Nickel Phosphide Composite

As a class of compounds having a specific structure, transition metal phosphides have attracted lots of attention and been widely used in electronics, magnetism, optics, ceramic materials, catalysis and other fields. Nickel phosphide, as one of the most important member of transition metal phosphides, exhibits unique properties in the optical, electrical and semiconductors. It is not only good corrosion resistance, abrasion resistance, anti-oxidation and waterproof materials, but also has a very impressive applications in the lithium-ion battery electrode materials and catalytic materials. Especially as the catalysts for hydrogenation desulfurization and denitrification, it has become the most forefront of research. In recent years, nickel phosphide gradually exhibits unique physical and chemical properties in photocatalysis. However, due to low separation efficiency of photo-generated electron-hole pairs, its performance in the application of photocatalysis has been significantly impaired. Therefore, in order to improve its photo-generated electron-hole separation efficiency and enhance its adsorption properties, to obtain a more excellent performance of nickel phosphide composites has attracted a lot of research interest.In this paper, hydrothermal method, chemical precipitation method and other methods have been used in preparing a series of nickel phosphide composites. Then, their morphology, phase and photocatalytic degradation performance have been studied. And compared with pure nickel phosphide, their photocatalytic degradation mechanism have been discussed in the last. The main contents are as follows:(1) Based on the "Ostwald ripening" mechanism, Ni2P microspheres with hollow structures were successfully synthesized via a facile template-free method. Ni2P hollow microspheres demonstrated a higher photocatalytic degradation activity in photocatalytic degradation reaction for Methylene Blue aqueous solution, which may be attributed to its larger specific surface area and morphology. Meanwhile, as anode materials for lithium ion batteries, the initial discharge capacity of Ni2P hollow microspheres was as high as 660 mAh/g, and it also has a great stability.(2) At a low temperature, core/shell Ni2P/ZnO composites were successfully prepared by using Ni2P microspheres as precursors and Zn(CH3COO)2·2H2O and NaOH as reactants. After FE-SEM characterization, it was found that ZnO nanoparticles were deposited on the surface of Ni2P microspheres, and some even assemble to form a worm-like structure. In addition, compared with pure Ni2P and ZnO, Ni2P/ZnO composites exhibit enhanced photocatalytic degradation activity, which may be due to its increased specific surface area and the highly separated efficiency of photo-generated electron-hole pairs.(3) Ni2P/ZnS and Ni2P/CdS composites were synthesized using a simple chemical precipitation. The products were characterized by XRD, EDX and FE-SEM. Finally, their photocatalytic properties have been tested by degradation of methylene blue. By comparison, it was found the photocatalytic activity of Ni2P/CdS is better than Ni2P/ZnS.(4) Using Ni2P microspheres as precursors, FeCl3·H2O and CH3COONa·3H2O as reactants, Ni2P/Fe3O4 composites were prepared by hydrothermal method in ethylene glycol solvent. The product were characterized and found Ni2P/Fe3O4 composites were composed of hexagonal phase Ni2P microspheres and cubic phase Fe3O4 nanoparticle located on the surface of Ni2P microspheres. The Ni2P/Fe3O4 composites have excellent photocatalytic properties and were easy for speration and recycling.