Electrochemical Synthesis of Tb−Co Alloy Nanoparticle Aggregates and Their Magnetic Properties

Li, Gao‐Ren; Zhang, Zi-Shou; Su, Cheng‐Yong; Tong, Yexiang

doi:10.1021/jp805051p

Cited by 6 publications

(4 citation statements)

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“…Development of bimetallic or trimetallic nanostructured materials, particularly alloy or core–shell nanoparticles (NPs), has attracted much recent attention because of their novel catalytic, , magnetic, − and optical properties, , which could be significantly different from those of their constituent single-metallic materials. The “alloy” properties of these nanoalloys are found to depend not only on their relative compositions and crystal structures but also on their sizes and shapes .…”

Section: Introductionmentioning

confidence: 99%

Phase-Induced Shape Evolution of FeNi Nanoalloys and Their Air Stability by in-Situ Surface Passivation

et al. 2013

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Shape and size of nanoparticles are fundamental structural properties that govern the development of novel surface-related applications. Traditionally external agents such as surfactants, reducing agents, or stabilizers have been used for enforcing preferential growth orientation, size, and shape to develop tailor-made nanoparticles. However, these external agents cover the pristine surface of the particle and invariably reduce the surface activity. Here, we introduce a surfactant-free, single-step electrochemical method to control the shape of air-stable FeNi alloy nanoparticles. Using glancing-incidence X-ray diffraction, we further demonstrate that the shape evolution of nanoparticles from concave cube to truncated sphere occurs concurrently with the phase transformation from bcc to fcc. This shape evolution can be achieved by fine-tuning a single parameter, the ratio of reactant concentrations (i.e., [Ni2+]/[Fe2+]). Addition of Ni2+ to the Fe2+ electrolyte changes the nucleation mechanism from progressive growth for pure Fe2+ electrolyte to instantaneous growth for mixed Fe2+/Ni2+ electrolyte, which leads to a remarkably narrow size distribution and very uniform dispersion on the Si substrate. Depth-profiling X-ray photoelectron spectroscopy and energy-dispersive X-ray analysis by both transmission electron microscopy and scanning electron microscopy for nanoparticles at different growth stages reveal alloy formation and preferential deposition of Fe during initial growth that results in a quasi-core–shell structure. We also observe the in-situ formation of a very thin Ni-doped FeOOH outer layer and NiFe2O4 intermediate layer on the skin of the nanoparticles, which passivates the surface and dramatically enhances the air stability. The present work provides a unique example of shape-controlled bimetallic nanostructures and offers insights into growth modification of a host metal structure by a guest metal.

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Section: Introductionmentioning

confidence: 99%

Phase-Induced Shape Evolution of FeNi Nanoalloys and Their Air Stability by in-Situ Surface Passivation

et al. 2013

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“…The understanding of these systems needs to be extended because of their potential applications in ICT and biological areas13. However, quantitative study of these systems is difficult because the generally used chemical synthesis methods are challenged in producing ultra-small particles that are size/shape monodispersed and are uniformly dispersed in solution or on a substrate1718. Further, defining the relationship between nanoparticle crystal structure and their magnetic properties is difficult because of the dimensional non-uniformity and using diffraction techniques for the study of very small dimensions.…”

mentioning

confidence: 99%

Size and space controlled hexagonal arrays of superparamagnetic iron oxide nanodots: magnetic studies and application

Ghoshal

Maity²,

Senthamaraikannan

et al. 2013

Sci Rep

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Highly dense hexagonally arranged iron oxide nanodots array were fabricated using PS-b-PEO self-assembled patterns. The copolymer molecular weight, composition and choice of annealing solvent/s allows dimensional and structural control of the nanopatterns at large scale. A mechanism is proposed to create scaffolds through degradation and/or modification of cylindrical domains. A methodology based on selective metal ion inclusion and subsequent processing was used to create iron oxide nanodots array. The nanodots have uniform size and shape and their placement mimics the original self-assembled nanopatterns. For the first time these precisely defined and size selective systems of ordered nanodots allow careful investigation of magnetic properties in dimensions from 50 nm to 10 nm, which delineate the nanodots are superparamagnetic, well-isolated and size monodispersed. This diameter/spacing controlled iron oxide nanodots systems were demonstrated as a resistant mask over silicon to fabricate densely packed, identical ordered, high aspect ratio silicon nanopillars and nanowire features.

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“…Magnetic alloy nanoparticles have drawn much attention as attractive materials in magnetic resonance imaging, drug targeting, magnetic refrigeration systems, ferrofluids, and catalysis for their improved magnetic, catalytic, and optical properties. [1][2][3] Specifically, such rare earth-transition metal (RE-TM) alloy nanoparticles as Co-Sm, Sm-Fe-N, and Nd-Fe-B are well-known for their remarkable magnetic properties, which have wide applications in the field of micro electro mechanical system (MEMS), consumer electronics, automobile, military equipment, and magnetic storage industries. [4][5][6][7][8][9][10][11][12] Various attempts have been made to prepare magnetic alloy nanoparticles by different methods.…”

mentioning

confidence: 99%

“…However, the reports on the electrochemical preparation of such alloy nanoparticles are limited. 2,3,13 Nowadays, Co-Sm is considered as an important material in MEMS because of its high Curie temperature and excellent thermal stability as compared with Nd-based alloys. [14][15][16][17] It has already been revealed the potential to produce nanometer structures with excellent magnetic properties.…”

mentioning

confidence: 99%

Electrochemical Preparation of Cobalt-Samarium Nanoparticles in an Aprotic Ionic Liquid

Manjum

Serizawa

Ispas

et al. 2020

J. Electrochem. Soc.

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Electrochemical preparation of Co-Sm nanoparticles was conducted in an aprotic room temperature ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing Co(TFSA)2 and Sm(TFSA)3. The cyclic voltammetry on a glassy carbon (GC) electrode indicated the electrochemically generated Sm(II) reacted with Co(II) at 25 °C. Potentiostatic cathodic reduction on a GC electrode in BMPTFSA containing 30 mM Co(TFSA)2 and 5 mM Sm(TFSA)3 at 25 °C gave the deposits, which were found to be composed of Co and Sm by energy dispersive X-ray spectroscopy (EDX). The deposits were found to be the aggregates of SmCo7 nanoparticles by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The formation of SmCo7 nanoparticles dispersed in the ionic liquid was also confirmed by TEM. SmCo7 nanoparticles were considered to form by the disproportionation reaction of Sm(II) in the presence of elementary Co, which was formed by the reduction of Co(II) by Sm(II).

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Electrochemical Synthesis of Tb−Co Alloy Nanoparticle Aggregates and Their Magnetic Properties

Cited by 6 publications

References 50 publications

Phase-Induced Shape Evolution of FeNi Nanoalloys and Their Air Stability by in-Situ Surface Passivation

Phase-Induced Shape Evolution of FeNi Nanoalloys and Their Air Stability by in-Situ Surface Passivation

Size and space controlled hexagonal arrays of superparamagnetic iron oxide nanodots: magnetic studies and application

Electrochemical Preparation of Cobalt-Samarium Nanoparticles in an Aprotic Ionic Liquid

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