Synthesis, Characterization And Properties Of Nickel Phosphide Mirco-/Nano-materials

Nickel phosphides exist in a variety of phases (e.g. Ni₂P, Ni₃P, Ni₅P₂, Ni₈P₃ and Ni₁₂P₅), and have broad industrial applications, especially in the field of catalysis. Also, nickel phosphides are currently of great scientific interest in materials science due to their novel semiconducting properties and potential applications in many fields including electron, magnetism, data storage, corrosion-resistant, oxidation-resistant, environment protection, etc. To date, a series of nickel phosphide mirco-/nano-materials have been successfully prepared by many groups through various methods and approaches. However, precious solvents, highly toxic reagents or higher temperature are often needed in the above methods. In order to conquer these shortcomings, some attempts to prepare nickel phosphide nanocrystals with certain shape in the system containing water were done in the past several years. However, it is still a huge challenge to search a nontoxic phosphorus source with low cost and high activity to prepare morphology-, phase- and size-controlled nickel phosphide mirco-/nano-materials in the water-containing system. In this dissertation, some nickel phosphide micro-/nano-materials were successfully synthesized by the solvothermal route. Simultaneously, the correlation between the morphology, phase and property of the as-obtained product was investigated. Main contents are listed as below:1. Nickel phosphide nanocrystals with various phases have been successfully synthesized via a simple solvothermal route employing nickel chloride (NiC_l2·6H₂O) and white phosphorus (WP) as starting reactants in the presence of sodium dodecylbenzene sulfonate (SDBS). X-ray powder diffraction (XRD) research showed that the pure Ni₁₂P₅ phase with a high yield could be obtained in an ethanol solution, and the pure Ni₂P form was prepared in a mixed system with the volume ratio of water/ethanol of 10:10. Furthermore, in order to investigate the correlation between properties and phases, as a case, the photocatalytic degradation abilities of two nickel phosphide phases for organic dyes were compared.2. Urchin-like Ni-P microstructures with room-temperature magnetism have been successfully synthesized via a simple water– DMFsolvothermal route employing nickel chloride (NiC_l2·6H₂O) and hypophosphite (NaH₂PO₂·H₂O) as starting reactants. Experiments showed that the morphology of the product could be affected by the molar ratio of Ni_<sup>2+/H₂PO₂^-, the volume ratio of water/DMF and the reaction temperature. The as-obtained product exhibits good capacity to rapidly remove heavy-metal ions such as Cd²⁺ and Pb²⁺ ions from water and can be easily recycled owing to their magnetism.3. One-dimensional nickel phosphide nanostructures have been successfully synthesized via a simple water–DMF solvothermal route employing NiC_l2·6H₂O and WP (white phosphorus) as starting reactants. Experiments showed that the morphology of the product could be affected by the amount of WP, the volume ratio of water/DMF and the reaction temperature.