Optimal synthesis and magnetic properties of size-controlled nickel phosphide nanoparticles

doi:10.1016/j.jallcom.2014.03.110

Journal of Alloys and Compounds

Volume 605, 25 August 2014, Pages 230-236

https://doi.org/10.1016/j.jallcom.2014.03.110 Get rights and content

Highlights

•
A pulse discharge method was used to synthesize noncrystalline Ni-P nanoparticles.
•
Size controlled nanoparticles were prepared through adjustment of reaction parameters.
•
Local structures both centered around Ni and P atoms were investigated including coordinated atoms and bondlengths.
•
Magnetic properties of the nickel phosphide nanoparticles are found to be ferromagnetic and size-dependent.

Abstract

Pulse discharge method was used in liquid phase to prepare nickel phosphide nanoparticles. The size and morphology of the as-prepared nanoparticles were found to be easily controlled through changing reaction parameters such as temperature, reactants concentration, reactants molar ratio, pulse discharge number, and pulse discharge voltage. The optimal reaction parameters have been obtained by single-factor experiments. X-ray diffraction, X-ray absorption fine structure spectra, Field Emission Scanning Electron Microscope, and Energy Dispersive X-ray Spectrum were used to characterize the as-prepared Ni–P nanoparticles. Vibrating Sample Magnetometer was used as magnetic measurements of the Ni–P nanoparticles. The results demonstrate that the as-prepared Ni–P nanoparticles are in amorphous phase, and consist of Ni and P elements. The P-content in the as-prepared Ni–P nanoparticles increases with the increasing of Ni–P particle size, and is independent on the initial concentration of P-concentration in the reaction solution. The Ni–P nanoparticles have totally about 12 near-neighbors of Ni–Ni and Ni–P around center Ni. The Ni–Ni distance increases with the increasing particle size. The as-prepared Ni–P nanoparticles present paramagnetic nature. Their saturated magnetizations are also size-dependent. The larger Ni–P particles has lower saturated magnetization, which can be attributed to the entrance of P into Ni lattice, causing a larger Ni–Ni separation and a looser, distorted local atomic structure.

Introduction

Nickel phosphides are a class of compounds that have properties similar to those of ordinary metallic compounds such as carbides, nitrides, borides and silicides. They are good conductors of heat and electricity and they have high thermal and chemical stability. Due to their properties of fundamental and commercial interest, transition metal phosphides have been used as excellent catalysts for hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) [1], electrocatalysts for hydrogen evolution reaction (HER) [2], magnetic storage for their magnetic properties [3], and electrode materials for Li batteries [4], [5]. Therefore, the synthesis of nickel phosphides has attracted extensive attention since several decades. Multiple synthesis routes, for example, the solid phase reaction [6], the solution-phase reaction [7], [8], [9], [10], the decomposition of single source precursors [11], the thermolysis of nickel compounds [12], and relatively inexpensive synthesis method [13], have been reported for the preparation of nickel phosphides with different shapes (solid particles, core–shell particles, rods, and wires) in recent years. Synthesis methods of amorphous nickel phosphide nanoparticles have also been developed [14], [15]. However, the report about size-controllable synthesis of Ni–P nanoparticles is scarce. Little is known about their local ordering and the implications of their structure on their novel properties due to the limitation of X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques [16].

Although techniques that enable the structure characterization of bulk material have been well-developed, the characterization of material at the nanoscale still presents significant challenges. The dominance of surface facets, small size and poor crystalline order makes characterization of nanoparticles difficult. X-ray absorption spectroscopy (XAS) is a method that has been used to resolve the structure of colloidal nanocrystals. With the use of the X-ray beam available through synchrotron radiation facility, XAS spectra can be obtained and used to gain insight into material structural properties [17], [18]. The structures of amorphous and crystalline phases can be determined through both X-ray-absorption near-edge-structure (XANES) spectrum to resolve geometric configuration, and extended X-ray-absorption fine-structure (EXAFS) to resolve radial structure, including interatomic distances, coordination numbers, and mean-squared disorder [19].

In this paper, a size-controllable preparation of nickel phosphide nanoparticles was performed through pulse discharge method. Reaction conditions such as temperature, solution concentration, reactants molar ratio, pulse number and pulse voltage were adjusted to obtain nanoparticles with different size distributions. Field Emission Scanning Electron Microscope (FESEM) pictures and Energy Dispersive X-ray Spectrum (EDS) spectra were collected through traditional laboratory experiments to determine morphology and composition of the as-prepared nanoparticles. XRD patterns and X-ray-absorption fine-structure (XAFS) spectra from both Ni K-edge and P K-edge were collected at Beijing Synchrotron Radiation Facility (BSRF) to resolve phase and atomic ordering. Size-dependent magnetic property was also measured through Vibrating Sample Magnetometer (VSM).

Section snippets

Preparation of samples

A pulsed-discharge method was used to prepare the Ni–P nanoparticles. The pulse discharge generator is home-made with a peak voltage of 1200 V and a peak current of 6 A. The schematic map of this one-step pulsed-discharge appliance is described in Fig. 1. Two commercially available reagents, i.e. nickel–sulfate hexahydrate (NiSO₄·6H₂O) and sodium hypophosphite (NaH₂PO₂·H₂O), were directly used as the raw materials without further purification. The preparation detail of the reaction solution is

Effects of reaction parameters on particle size distribution and morphology

In order to control the particle size of the as-prepared Ni–P nanoparticles, five groups of single-factor experiment were carried out under different temperatures, reactant concentrations, reactant ratios, pulse numbers and pulse voltages. Each impact of the five reaction parameters on the size-distribution and morphology of Ni–P nanoparticles were investigated. In these experiments, only one of the reaction parameters was variable at each time, while the others were kept constant. The detailed

Conclusion

Nickel phosphide nanoparticles were prepared through liquid pulse discharge method. The effect of reaction parameters on particle-size distribution and morphology of the as-prepared Ni–P nanoparticles has been studied. Generally, higher temperature and solution concentration are in favor of small particles, while the reactants molar ratio, pulse discharge number and pulse discharge voltage have optimal values for the synthesis of uniform Ni–P nanoparticles. Single-factor experiments were

Acknowledgement

This work was supported by National Natural Science Foundation (Nos. 51374019, U1232203, 10385008, 50374010) of China.

References (28)

B. Mauvernay et al.
Redox mechanism in the binary transition metal phosphide Cu₃P
J. Phys. Chem. Solids
(2006)
X. Zheng et al.
One-pot synthesis of hollow nickel phosphide nanoparticles with tunable void sizes using triphenylphosphine
Mater. Lett.
(2009)
Y. Chen et al.
Solution-phase synthesis of nickel phosphide single-crystalline nanowires
J. Cryst. Growth
(2009)
E.E. Finney et al.
Nanocluster nucleation and growth kinetic and mechanistic studies: a review emphasizing transition-metal nanoclusters
J. Colloid Interface Sci.
(2008)
S.L. Brock et al.
Recent developments in synthetic approaches to transition metal phosphide nanoparticles for magnetic and catalytic applications
J. Solid State Chem.
(2008)
S.A. Majetich et al.
Magnetic nanoparticles and magnetocrystalline anisotropy
Nanostruct. Mater.
(1997)
S. Ted Oyama
Novel catalysts for advanced hydroprocessing: transition metal phosphides
J. Catal.
(2003)
E.J. Popczun et al.
Nanostructured nickel phosphide as an electrocatalyst for the hydrogen evolution reaction
J. Am. Chem. Soc.
(2013)
J. Park et al.
Generalized synthesis of metal phosphide nanorods via thermal decomposition of continuously delivered metal-phosphine complexes using a syringe pump
J. Am. Chem. Soc.
(2005)
D.C.S. Souza et al.
A reversible solid-state crystalline transformation in a metal phosphide induced by redox chemistry
Science
(2002)

G. Shi et al.

New synthesis method for nickel phosphide nanoparticles: solid phase reaction of nickel cations with hypophosphites

J. Mater. Chem.

(2009)

M. Elayaraja et al.

Synthetic levers enabling independent control of phase, size, and morphology in nickel phosphide nanoparticles

ACS Nano

(2011)

X. Zheng et al.

Nickel/nickel phosphide core-shell structured nanoparticles: synthesis, chemical, and magnetic architecture

Chem. Mater.

(2009)

W. Maneeprakorn et al.

Synthesis of the nickel selenophosphinates [Ni(Se₂PR₂)₂] (R = ⁱPr, ^tBu and Ph) and their use as single source precursors for the deposition of nickel phosphide or nickel selenide nanoparticles

J. Dalton Trans.

(2009)

Cited by (13)

Pure phase Ni<inf>12</inf>P<inf>5</inf> anchored on N, P-codoped carbon nanosheet: A stable and highly efficient catalyst to reduce toxic organic compounds for continuous-flow application
2023, Applied Surface Science
The removal of toxic organic compounds from aqueous media through reduction reactions using nonnoble catalysts has attracted much attention in recent years. In this study, a simple method for the synthesis of pure-phase Ni₁₂P₅ nanoparticles supported on N, P-codoped carbon (NPC) sheets was developed, in which a nickel phosphine complex was selected as the precursor due to its high Ni/P ratio, air stability and easy preparation. By controlling the pyrolysis temperature, Ni_xP_y@NPC₇₀₀ with a high dispersity and exposed active sites can be obtained, which was characterized by XRD, HRTEM, EDS, XPS, Raman and NH₃-TPD. The catalytic performance of the composite in the reaction of 4-nitrophenol (4-NP) was assessed under mild conditions, exhibiting excellent catalytic activity with a low apparent activation energy E_a (29.87 KJ·mol⁻¹). In addition, the catalyst can be recycled without obvious loss of activity for up to ten successive cycles. The outstanding hydrogenation activity is ascribed to the exposed Ni₁₂P₅(3 1 2) crystal plane of Ni_xP_y@NPC₇₀₀, which is attributed to the lower energy barrier required to form a hydrogen splitting state according to DFT calculations. Moreover, Ni_xP_y@NPC₇₀₀ was creatively coated in a Teflon tube with Nafion as the adhesive and constructed as a fixed-bed device. The continuous-flow catalytic reaction shows that the catalyst can maintain a satisfactory efficiency for approximately 6 h in the reduction of 4-NP and methyl orange (MO). These findings suggest that Ni_xP_y@NPC₇₀₀ is an ideal catalyst for industrial applications for the chemical reduction of toxic compounds from wastewater.
Phase and morphology evolution of well-dispersed nickel phosphide nanocrystals and the abnormal ferromagnetic origin by experimental and theoretical studies
2023, Ceramics International
Thermal decomposition strategy has been widely used to fabricate well-dispersed size/shape-controlled metal phosphides, which have versatile structural and electronic characteristics. However, the underlying formation mechanism is still unclear. Herein, taking nickel phosphides as the example, the phase/morphology regulatory mechanism was studied in detail, and the intrinsic origin of eccentric ferromagnetism was investigated. The main findings are as follows: 1) The interdependent synthetic levers can manipulate the phase conversion from tetragonal Ni₁₂P₅ to hexagonal Ni₂P, with the morphology transformation from small solid to big hollow structure.; 2) The hollow structure is caused by Nanoscaled Kirkendall effect, while the accompanying growing particle size is attributed to Lamer mechanism and Ostwald ripening mechanism.; 3) Formation studies of Ni₂P shows that the phase evolution undergo the process of FCC Ni → amorphous Ni–P → tetragonal Ni₁₂P₅ → hexagonal Ni₂P, during which the morphology converts from small solid to large hollow structure. Dissolution-recrystallization process also plays an important role in the phase, size and shape evolution.; 4) The Ni₂P nanoparticles show abnormal size-dependent ferromagnetism, in which larger hollow particles show higher saturation magnetization. Annealing treatment experiments and first principles calculations clarify that the intrinsic ferromagnetic origin of Ni₂P is caused by P defect. This work deeply emerges the structural evolution and formation mechanism of nickel phosphides, and certifies the positive effect of P vacancy on the magnetic properties, which gives a sight to tail the metal phosphides to expand their applications.
Enhance the electromagnetic absorption performance of Co&Ni@GNs by designing appropriate cCo: cNi deposited on GNs surface
2020, Synthetic Metals
Citation Excerpt :
The presence of the P element destroys the crystallinity of the Co&Ni alloys, so the Co&Ni alloys exhibit a certain amorphous nature and exhibits a broad diffraction peak on the XRD patterns. According to the XRD patterns, it can be proved that the experimentally successful preparation of the Co&Ni@GNs composite material [15]. The Fig. 4 is the Raman spectra of the Co&Ni@GNs.
In this work, by using synthetic innovation and improved one-step hydrothermal method to deposit Co&Ni alloy on graphite nanosheets (GNs), Co&Ni@GNs with more stable absorbing performance was successfully prepared. Compared to Hummers process of GNs, the advantage of this work is is that the process of acidifying GNs is simple. Co&Ni@GNs exhibit tightly connected interfaces, this may contribute to interfacial polarization and defect dipole polarization, so EM (electromagnetic) waves absorption performance can be improved by increasing dielectric loss. The strong dielectric relaxation can be observed in Co-Ni@GNs-2 (cCo:cNi=3:2) samples, which further enhances the dielectric loss. The minimum reflection loss of Co-Ni@GNs-2 is -47.26 dB at 2.6 mm, and the effective absorption bandwidth is 3.72 GHz at 1.7 mm. At the 2–18 GHz, the Z_in/Z₀ value of Co-Ni@GNs-2 is closer to 1, indicating that EM waves is easier to enter the composite and has a higher attenuation constant. The modified one-step hydrothermal method is low-cost and shorter time, which could become an industrial technique to synthesize carbonaceous composites for electromagnetic absorption.
Optimization of electromagnetic wave absorbing properties for Ni-Co-P/GNs by controlling the content ratio of Ni to Co
2020, Journal of Magnetism and Magnetic Materials
Citation Excerpt :
More importantly, they have high thermal and chemical stability and good thermal conductivity. These unique properties make them promising as performance enhancing materials in graphene composite absorbing materials while maintaining graphene composites’ excellent EM wave absorption properties [35,36]. In this paper, we use a traditional electroless plating system, which uses a complexing agent to complex magnetic metal ions, and uses hydrothermal method to reduce it by a reducing agent at a certain temperature and pressure to make Ni-Co-P alloy directly grown on the surface of the graphene nanosheet to form Ni-Co-P alloy/graphene nanosheet (For convenience of reference, hereinafter referred to as Ni-Co-P/GNs) composite.
In this study, Ni-Co-P alloy were successfully grown on graphene nanosheets by one-step hydrothermal method to synthesize Ni-Co-P/graphene nanosheets (Ni-Co-P/GNs) composites. The effect of the content ratio of Ni to Co on the morphology and electromagnetic wave absorption properties of the composite were investigated. The results show that the content ratio of Ni to Co has a great influence on the morphology and electromagnetic wave absorption properties of Ni-Co-P/GNs. The content ratios of Ni to Co in the five samples were 9:1, 7:3, 5:5, 3:7, and 1:9, respectively. In terms of morphology, Ni-Co-P is uniformly grown on the surface of graphene nanosheets in a microspherical morphology, and the particle size of Ni-Co-P microspheres increase with the decrease of Ni content and the increase of Co content. And the distribution density on the surface of the GNs is reduced. In terms of EM wave absorbing properties, when the content ratio of Ni to Co is 5:5, Ni-Co-P/GNs exhibits the best EM wave absorbing properties of which the minimum reflection loss is −57.8 dB. When the content ratio of Ni to Co is 9:1, it has the widest effective absorption bandwidth of 3.6 GHz (11.7–15.3 GHz), and the corresponding minimum absorption loss (RL) also reaches −52.8 dB. When the content of Co is much higher than Ni, the electromagnetic wave absorbing properties of Ni-Co-P/GNs become poor. In addition, the best EM wave absorbing performance of Ni-Co-P/GNs at different content ratios all occur at the thickness of around 1.5 mm, which indicates that Ni-Co-P/GNs composites can meet the lightweight requirements of EM wave absorber. Ni-Co-P/GNs have the potential to be the candidates for EM wave absorber. It is of great significance to study the content ratio of Ni and Co for guiding the adjustment of the morphology and electromagnetic wave absorption properties of Ni-Co-P/GNs.
Size-dependent magnetic and electrocatalytic properties of nickel phosphide nanoparticles
2016, Applied Surface Science
Citation Excerpt :
Generally, the property of a material can be influenced by its microstructure such as crystalline phase, size and morphology [8–10]. For example, for magnetic field, Tan et al. synthesized Ni-P nanoparticles (NPs) with different sizes through pulse discharge method and demonstrated that the size effect in magnetic properties is existing [2]. Hyeon group synthesized Fe2P nanorods with different sizes and observed the size-dependent blocking temperatures for many nanorods with the cross-sections of 5–6 nm and the lengths from 43 to 290 nm [11].
Nickel phosphide (Ni₂P) nanoparticles (NPs) with different sizes were synthesized via thermal decomposition of bis(triphenylphosphine)nickel dichloride precursor in the presence of oleylamine. The size of the as-synthesized Ni₂P NPs could easily be controlled by increasing the reaction temperature from 300 to 340 °C. The structure and morphology were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N₂ adsorption–desorption and X-ray photoelectron spectroscopy (XPS). Then the influences of the size of the Ni₂P NPs on the magnetic and electrocatalytic properties were investigated systematically. The results indicate that the as-synthesized Ni₂P NPs exhibit ferromagnetic characteristic at 5 K. The Ni₂P NPs with small size exhibit superparamagnetism and the larger size exhibit ferromagnetic characteristic at 300 K. The blocking temperature, saturation magnetization, remanent magnetization and coercivity increased significantly with the increase of size of Ni₂P NPs, indicating the strong size effect of Ni₂P NPs for magnetic properties. Electrochemical tests indicate that the catalytic activity can be enhanced by decreasing the size of Ni₂P NPs. Due to the larger electrochemical active surface area and higher electrical conductivity, the Ni₂P NPs with small size exhibit higher electrocatalytic activity. This work suggests that the size of Ni₂P NPs is an important factor to affect the magnetic and electrocatalytic properties.
Noncrystalline structure of Ni-P nanoparticles prepared by liquid pulse discharge
2015, Journal of Synchrotron Radiation

View all citing articles on Scopus

View full text

Optimal synthesis and magnetic properties of size-controlled nickel phosphide nanoparticles

Highlights

Abstract

Introduction

Section snippets

Preparation of samples

Effects of reaction parameters on particle size distribution and morphology

Conclusion

Acknowledgement

J. Phys. Chem. Solids

Mater. Lett.

J. Cryst. Growth

J. Colloid Interface Sci.

J. Solid State Chem.

Nanostruct. Mater.

Novel catalysts for advanced hydroprocessing: transition metal phosphides

J. Catal.

Nanostructured nickel phosphide as an electrocatalyst for the hydrogen evolution reaction

J. Am. Chem. Soc.

Generalized synthesis of metal phosphide nanorods via thermal decomposition of continuously delivered metal-phosphine complexes using a syringe pump

J. Am. Chem. Soc.

A reversible solid-state crystalline transformation in a metal phosphide induced by redox chemistry

Science

New synthesis method for nickel phosphide nanoparticles: solid phase reaction of nickel cations with hypophosphites

J. Mater. Chem.

Synthetic levers enabling independent control of phase, size, and morphology in nickel phosphide nanoparticles

ACS Nano

Nickel/nickel phosphide core-shell structured nanoparticles: synthesis, chemical, and magnetic architecture

Chem. Mater.

Synthesis of the nickel selenophosphinates [Ni(Se2PR2)2] (R = iPr, tBu and Ph) and their use as single source precursors for the deposition of nickel phosphide or nickel selenide nanoparticles

J. Dalton Trans.

Synthesis of the nickel selenophosphinates [Ni(Se₂PR₂)₂] (R = ⁱPr, ^tBu and Ph) and their use as single source precursors for the deposition of nickel phosphide or nickel selenide nanoparticles