Nano-Micro Letters

Synthesis and Thermal Behavior of Metallic Cobalt Micro and Nanostructures

Marlene González Montiel1, P. Santiago-Jacinto2, J. A. I. Díaz Góngora1 E. Regueraand Geonel Rodríguez-Gattorno1,3,

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Nano-Micro Letters, , Volume 3, Issue 1, pp 12-19
Publication Date (Web): April 7, 2011 (Article)




Figure 1 Representative XRD patterns for: a) all the as-prepared Co nanoparticles from borohydride reduction; b) using hydrazine as reducer, d) sample showed in a) after annealing at 500°C; c) and e) Column bar plots correspond to hcp Co- JCPDS # 01-1278 and fcc Co-JCPDS # 15-0806, respectively.

In this contribution, a comparative study of metallic cobalt micro and nanoparticles obtained in solution by four different chemical routes is reported. Classic routes such as borohydride reduction in aqueous media and the so-called poly-ol methodology were used to obtain the cobalt nanostructures to be studied. Using CTAB as surfactant, cobalt hollow nanostructures were obtained. The use of strong reducing agents, like sodium borohydride, favors the formation of quasi-monodispersed nanoparticles of about 2 nm size but accompanied of impurities; for hydrazine (a mid reducer), nanoparticles of larger size are obtained which organize in spherical microagglomerates. Valuable information on the particles thermal stability and on nature of the species anchored at their surface was obtained recording the thermogravimetric curves. The samples to be studied were characterized from UV-vis, IR, X-ray diffraction, and electron microscopy images (scanning and transmission).



Metallic Cobalt; Cobalt nanoparticles; Magnetic nanoparticles; Hollow magnetic microparticles


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