The structural evolution and diffusion during the chemical transformation from cobalt to cobalt phosphide nanoparticles

Ha, Don‐Hyung; Moreau, Liane M.; Bealing, Clive R.; Zhang, Haitao; Hennig, Richard G.; Robinson, Richard D.

doi:10.1039/c1jm10337g

Cited by 140 publications

(170 citation statements)

References 64 publications

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“…Based on the breadth of the peak and the absence of any higher order reflections, we presume this to be a metal-P amorphous alloy. 35,45,46 The absence of CoO is attributed to reduction to fcc Co metal by oleylamine at this temperature, as observed by Nam et al 47 When the intermediate temperature was increased to 290 °C, the formation of crystalline NiCoP was observed (Figure 7c), indicating this temperature is sufficient to crystallize the material. The particle size is slightly larger (8.8 nm from the PXRD data and 12.24 ± 1.72 nm from TEM) than that obtained at 350 °C and some hollow particles are observed (Figure 7c).…”

Section: Effect Of Intermediate Heating Temperature and Heating Time supporting

confidence: 57%

“…The formation of hollow particles may be attributed to the diffusion rate differences between metals and P, according to the Kirkendall effect. 34 In previous studies the formation of hollow particles for cobalt phosphides has also been noted, 35 suggesting that Co is a highly mobile metal within the phosphide lattice.…”

Section: Table 1 Ni:co Target and Actual (As Assessed By Eds) Metal mentioning

confidence: 95%

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Simultaneous Control of Composition, Size, and Morphology in Discrete Ni_2–xCo_xP Nanoparticles

et al. 2015

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A synthetic protocol developed to produce phase-pure, nearly monodisperse Ni 2-x Co x P nanoparticles (x≤1.7) is described. The Ni 2-x Co x P particles vary in size, ranging from 9-14 nm with standard deviations of <20% (based on TEM analysis) and the actual metal ratios obtained from EDS closely follow the targeted ratios. With increasing Co, samples with larger size distributions are obtained and include particles with voids, attributed to the Kirkendall effect. In order to probe the mechanism of ternary phosphide particle formation, detailed studies were conducted for Ni:Co = 1:1 as a representative composition. It was revealed that the P:M ratio, heating temperature and heating time have a large impact on the nature of both intermediate and final crystalline particles formed. By tuning these conditions, nanoparticles can be produced with different sizes (from ca 7-25 nm) and morphol0gy (hollow vs. dense).

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Section: Effect Of Intermediate Heating Temperature and Heating Time supporting

confidence: 57%

Section: Table 1 Ni:co Target and Actual (As Assessed By Eds) Metal mentioning

confidence: 95%

Simultaneous Control of Composition, Size, and Morphology in Discrete Ni_2–xCo_xP Nanoparticles

et al. 2015

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“…It is known that oleate binds slightly more strongly to (100) planes on metal oxide surfaces. [10] During the early stage of phosphidation, the oleate hinders the Pdiffusion on the (100) planes,f avoring the M-P growth along < 111 > / < 110 > directions into the concave shape and further into the seaurchin structure.The nanourchin structure formation is due to the associated growth of the circularly distorted Co 2 Pand the wire shaped Fe 2 P [11] (Supporting Information, Figure S1). Thec omplete transformation of the Co-Fe-O nanocubes into Co-Fe-P nanourchins was confirmed by X-ray diffraction (XRD) patterns ( Figure 3A).…”

Section: Methodsmentioning

confidence: 98%

Controlled Anisotropic Growth of Co‐Fe‐P from Co‐Fe‐O Nanoparticles

et al. 2015

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A facile approach to bimetallic phosphides, Co-Fe-P, by a high-temperature (300 °C) reaction between Co-Fe-O nanoparticles and trioctylphosphine is presented. The growth of Co-Fe-P from the Co-Fe-O is anisotropic. As a result, Co-Fe-P nanorods (from the polyhedral Co-Fe-O nanoparticles) and sea-urchin-like Co-Fe-P (from the cubic Co-Fe-O nanoparticles) are synthesized with both the nanorod and the sea-urchin-arm dimensions controlled by Co/Fe ratios. The Co-Fe-P structure, especially the sea-urchin-like (Co(0.54)Fe(0.46))2P, shows enhanced catalysis for the oxygen evolution reaction in KOH with its catalytic efficiency surpassing the commercial Ir catalyst. Our synthesis is simple and may be readily extended to the preparation of other multimetallic phosphides for important catalysis and energy storage applications.

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“…Finally, selective ion diffusion can be used for the elaboration of novel core/shell structures, which do not contain obligatorily a cavity. An example is the transformation of ǫ-Co nanoparticles into Co/Co-P core/shell structures containing an amorphous cobalt phosphide shell [92]. This intermediate structure is obtained by inward P diffusion preceding the complete transformation of ǫ-Co into Co 2 P nanoparticles through subsequent outward Co diffusion accompanied by Kirkendall hollowing.…”

Section: Hollow Structuresmentioning

confidence: 99%

Engineered inorganic core/shell nanoparticles

et al. 2014

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It has been for a long time recognized that nanoparticles are of great scientific interest as they are effectively a bridge between bulk materials and atomic structures. At first, size effects occurring in single elements have been studied. More recently, progress in chemical and physical synthesis routes permitted the preparation of more complex structures. Such structures take advantages of new adjustable parameters including stoichiometry, chemical ordering, shape and segregation opening new fields with tailored materials for biology, mechanics, optics magnetism, chemistry catalysis, solar cells and microelectronics. Among them, core/shell structures are a particular class of nanoparticles made with an inorganic core and one or several inorganic shell layer(s). In earlier work, the shell was merely used as a protective coating for the core. More recently, it has been shown that it is possible to tune the physical properties in a larger range than that of each material taken separately. The goal of the present review is to discuss the basic properties of the different types of core/shell nanoparticles including a large variety of heterostructures. We restrict ourselves on all inorganic (on inorganic/inorganic) core/shell structures. In the light of recent developments, the applications of inorganic core/shell particles are found in many fields including biology, chemistry, physics and engineering. In addition to a representative overview 2 of the properties, general concepts based on solid state physics are considered for material selection and for identifying criteria linking the core/shell structure and its resulting properties. Chemical and physical routes for the synthesis and specific methods for the study of core/shell nanoparticle are briefly discussed.

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The structural evolution and diffusion during the chemical transformation from cobalt to cobalt phosphide nanoparticles

Cited by 140 publications

References 64 publications

Simultaneous Control of Composition, Size, and Morphology in Discrete Ni_2–xCo_xP Nanoparticles

Simultaneous Control of Composition, Size, and Morphology in Discrete Ni_2–xCo_xP Nanoparticles

Controlled Anisotropic Growth of Co‐Fe‐P from Co‐Fe‐O Nanoparticles

Engineered inorganic core/shell nanoparticles

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The structural evolution and diffusion during the chemical transformation from cobalt to cobalt phosphide nanoparticles

Cited by 140 publications

References 64 publications

Simultaneous Control of Composition, Size, and Morphology in Discrete Ni2–xCoxP Nanoparticles

Simultaneous Control of Composition, Size, and Morphology in Discrete Ni2–xCoxP Nanoparticles

Controlled Anisotropic Growth of Co‐Fe‐P from Co‐Fe‐O Nanoparticles

Engineered inorganic core/shell nanoparticles

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Simultaneous Control of Composition, Size, and Morphology in Discrete Ni_2–xCo_xP Nanoparticles

Simultaneous Control of Composition, Size, and Morphology in Discrete Ni_2–xCo_xP Nanoparticles