Synthesis of Co–50Ni nanocrystals obtained by a modified polyol method

Bregado-Gutiérrez, Julio; Saldívar-García, Armando J.; López, H. F.

doi:10.1016/j.matlet.2007.07.076

Cited by 16 publications

(9 citation statements)

References 15 publications

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“…S2b). 20 Ni 80 alloy product formed at 200 °C for 10h with surfactant diethylenetriamine (DETA) in the reaction system. 2d), and most of them grow into overlapping nanoflakes, the flower-like microsphere is obtained (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Electron holography observation was carried out with a specially designed JEM-2100F TEM. Otherwise, surface architecture with irregular groove defects could be observed onside the surface of ball-like Co 20 Ni 80 particles without NaOH (Fig. A high-resolution TEM (HRTEM) image of flower-like microsphere demonstrates that there is an interplanar spacing of about 0.22 nm, which corresponds to the (111) plane of the Co 20 Ni 80 alloy (the inset of Fig.…”

Section: Characterizationmentioning

confidence: 99%

“…XRD patterns of the four different morphologies Co20 Ni 80 alloy (a). EDS pattern of the flower-like Co 20 Ni 80 microsphere (b).…”

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confidence: 99%

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Dependency of magnetic microwave absorption on surface architecture of Co₂₀Ni₈₀hierarchical structures studied by electron holography

et al. 2015

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To design and fabricate rational surface architecture of individual particles is one of the key factors that affect their magnetic properties and microwave absorption capability, which is still a great challenge. Herein, a series of Co20Ni80 hierarchical structures with different surface morphologies, including flower-, urchin-, ball-, and chain-like morphologies, were obtained using structure-directing templates via a facile one-step solvothermal treatment. The microwave reflection loss (RL) of urchin-like Co20Ni80 hierarchical structures reaches as high as -33.5 dB at 3 GHz, with almost twice the RL intensity of the ball- and chain-like structures, and the absorption bandwidth (<-10 dB) is about 5.5 GHz for the flower-like morphology, indicating that the surface nanospikes and nanoflakes on the Co20Ni80 microsphere surfaces have great influences on their magnetic microwave absorption properties. Electron holography analysis reveals that the surface nanospikes and nanoflakes could generate a high density of stray magnetic flux lines and contribute a large saturation magnetization (105.62 emu g(-1) for urchin-like and 96.41 emu g(-1) for flower-like morphology), leading the urchin-like and flower-like Co20Ni80 to possess stronger microwave RL compared with the ball-like and chain-like Co20Ni80 alloys. The eddy-current absorption mechanism μ''(μ')(-2)(f)(-1) is dominant in the frequency region above 8 GHz, implying that eddy-current loss is a vital factor for microwave RL in the high frequency range. It can be supposed from our findings that different surface morphologies of magnetic hierarchical structures might become an effective path to achieve high-performance microwave absorption for electromagnetic shielding and stealth camouflage applications.

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Section: Resultsmentioning

confidence: 99%

Section: Characterizationmentioning

confidence: 99%

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Dependency of magnetic microwave absorption on surface architecture of Co₂₀Ni₈₀hierarchical structures studied by electron holography

et al. 2015

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“…For decades, various fine metallic and alloy powders were prepared by the reduction of appropriate precursor such as Au, Ag, Co, Ni, and Fe 3 O 4 in liquid polyol, which plays the role of reducing agent and the crystal growth medium for the particles [11][12][13]. It is possible to obtain fine particles with a good morphology and a narrow size distribution through the polyol method.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and electrochemical properties of Li2MnSiO4/C nanoparticles via polyol process

Wang

Yang

2010

Rare Metals

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Carbon-coated lithium manganese silicate (Li 2 MnSiO 4 /C) nanoparticles were synthesized by polyol process. X-ray diffraction (XRD) patterns of the obtained materials exhibit a good fit with that of the Li 2 MnSiO 4 phase. Field emission scanning electron microscopy (FESEM) images of the obtained samples show that the particle size is only tens of nanometers. The high resolution transmission electron microscopy (HRTEM) analysis shows that the Li 2 MnSiO 4 nanoparticles are surrounded by a very thin film of amorphous carbon. The composite prepared through polyol process shows good performance as cathode materials in lithium cells at room temperature. The charge capacity of the Li 2 MnSiO 4 /C samples is 219 mAh/g (about 1.3 Li + per unit formula extracted), and the discharge capacity is 132 mAh/g (about 0.8 Li + per unit formula inserted) in the first cycle in the voltage range of 1.5-4.8 V. A good capacity cycling maintenance of 81.8% after 10 cycles was obtained.

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“…DRX, este material é composto basicamente por óxido de níquel e alguns estudos apontam a formação de uma camada passivante em superfícies de NiO, a qual inicialmente apresenta-se ativa frente a oxidação do álcool, entretanto, posteriormente, torna-se inativa com a formação da camada passivante γ-NiOOH[35,36,63].Figura 17: Perfis de TPR para materiais sintetizados pelo método da impregnação sem posterior tratamento térmico. (a) materiais monometálicos (b) materiais bi e tri metálicos.Daniel e Jeevanandam (2011)[77], ligas de CoNi apresentam três picos característicos da estrutura fcc com os ângulos de difração em 44°, 51° e 76° atribuídos as fases (111), (200) e (220) respectivamente[77,78]. Estes picos são muito próximos aos valores encontrados para o…”

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Estudos da atividade de catalisadores a base de níquel, suportados em carbono, para a eletrooxidação do glicerol

Oliveira¹

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Meus sinceros agradecimentos a todos que colaboraram de alguma forma durante o desenvolvimento desse trabalho, com discussões cientificas, momentos de descontração, força e apoio. Dessa maneira, não poderia deixar de agradecer: Ao professor Dr. Germano Tremiliosi Filho, pela orientação, oportunidade, discussões científicas, conselhos e por confiar em meu trabalho. A Fapesp (processo 2008/11601-7) pela concessão de bolsa de doutorado e apoio financeiro no país e a Capes (processo 5444110) pela bolsa concedida no exterior. Ao departamento de Físico-Química, assim como o Programa de Pós-Graduação, o setor de convênios, mecânica, vidraria. A todos os funcionários que foram essenciais em algum momento, e em especial a Silvia, Andreia e Gustavo por sempre serem tão solícitos e dispostos a ajudar. Aos técnicos do laboratório Jonas, Paulo e Gabriel pela ajuda na montagem dos experimentos bem como a conversa nas horas vagas. Valdecir e Mauro pelas discussões de resultados, conselhos e apoio ao longo do trabalho. Ao professor Valderes por ceder materiais da rota hidrotérmica para estudo e também por permitir que eu utilizasse seu laboratório para a síntese destes materiais. Je voudrais adresser mes sincères remerciements au Professeur Dr. Boniface K. Kokoh pour avoir accepté de m'accueillir dans son laboratoire, laboratoire au sein duquel a été effectuée une bonne partie de ce travail. Professeur, votre pleine disponibilité, la richesse scientifique des discussions que nous avons eues, vos précieux conseils et votre amitié m'ont été d'un secours inestimable. J'exprime toute ma gratitude et mes considérations distinguées à M. Têko W. Napporn et, Mmes Karine Servat et Cláudia Morais dudit laboratoire pour leur disponibilité et tous leurs apports au cours de mon long séjour. Par ailleurs, je tiens à remercier tous les amis que je me suis fait en France. Il s'agit en l'occurrence de Seydou,

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Synthesis of Co–50Ni nanocrystals obtained by a modified polyol method

Cited by 16 publications

References 15 publications

Dependency of magnetic microwave absorption on surface architecture of Co₂₀Ni₈₀hierarchical structures studied by electron holography

Dependency of magnetic microwave absorption on surface architecture of Co₂₀Ni₈₀hierarchical structures studied by electron holography

Synthesis and electrochemical properties of Li2MnSiO4/C nanoparticles via polyol process

Estudos da atividade de catalisadores a base de níquel, suportados em carbono, para a eletrooxidação do glicerol

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Synthesis of Co–50Ni nanocrystals obtained by a modified polyol method

Cited by 16 publications

References 15 publications

Dependency of magnetic microwave absorption on surface architecture of Co20Ni80hierarchical structures studied by electron holography

Dependency of magnetic microwave absorption on surface architecture of Co20Ni80hierarchical structures studied by electron holography

Synthesis and electrochemical properties of Li2MnSiO4/C nanoparticles via polyol process

Estudos da atividade de catalisadores a base de níquel, suportados em carbono, para a eletrooxidação do glicerol

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Dependency of magnetic microwave absorption on surface architecture of Co₂₀Ni₈₀hierarchical structures studied by electron holography

Dependency of magnetic microwave absorption on surface architecture of Co₂₀Ni₈₀hierarchical structures studied by electron holography