Shape-controlled synthesis and performance comparison of Ni2P nanostructures

Abstract

In this paper, a facile precursor phosphidation route was designed for morphology controlled synthesis of Ni₂P nanostructures, employing NiCl₂ and NaH₂PO₂ as the initial reactants in the presence of polyvinylpyrrolidone (PVP) and hexamethylenetetramine (HMT). Experiments showed that under the same hydrothermal conditions, NiHPO₃·H₂O nanorods and Ni nanospheres were separately obtained via only changing the original amount of HMT. The as-obtained NiHPO₃·H₂O nanorods and Ni nanospheres could be used as the precursors in low-temperature phosphidation reactions under a N₂ atmosphere. Under the same phosphidation conditions, Ni₂P nanorods and nanospheres were formed, respectively. The precursor and the final products were characterized by powder X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical performance and the catalytic properties of the Ni₂P nanorods and nanospheres were investigated. It was found that the as-obtained Ni₂P nanostructures displayed marked shape-dependent properties: the Ni₂P nanorods presented better electrochemical performance, such as higher specific capacitance and more stable cycle features, and stronger catalytic activity for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in an excess NaBH₄ solution than the Ni₂P nanospheres.