The synthesis and arrested oxidation of amorphous cobalt nanoparticles using DMSO as a functional solvent

  • Jennifer N. Duggan
  • Michael J. Bozack
  • Christopher B. Roberts
Research Paper


Magnetic nanoparticles exhibit a strong tendency to become overly oxidized and unstable during synthesis, ultimately leading to nanoparticle agglomeration and degradation. Capping agents can be used during nanoparticle synthesis to provide particle surface coverage and to improve nanoparticle dispersibility in solution, while preventing excessive oxidation and agglomeration. This paper presents a technique to synthesize amorphous 3.7 ± 1.5 nm cobalt (Co) nanoparticles using dimethyl sulfoxide (DMSO) to function as both the stabilizing agent and the solvent for Co nanoparticles via a quick, solvent-based reduction of Co2+ with NaBH4 in a DMSO solvent. UV–visible spectroscopy analysis was used to determine the minimum amount of reducing agent needed to produce Co nanoparticles so as to limit the waste of reagents. TEM and SEM imaging were used to study the morphology of the Co nanoparticles from the DMSO dispersion and of the Co nanoparticle powder. FT-IR was used to elucidate the nature of the interaction between the Co nanoparticle surface and DMSO. Furthermore, SEM–EDS elemental mapping was used to determine the composition and surface properties of the Co nanoparticles. This synthesis method demonstrates that Co nanoparticles can be successfully synthesized by simply using DMSO as a functional solvent, thereby avoiding excessive oxidation and agglomeration in solution.


Cobalt Co Nanoparticle Synthesis Dimethyl sulfoxide DMSO Functional solvent Amorphous Oxidation 



The authors gratefully acknowledge the financial support from the U.S. Department of Energy (grant No. EE0003115), the USDA AFRI program (Grant No. 2011-68005-30410), and the Gulf of Mexico Research Initiative (Grant No. SA 12-05/GoMRI-002). The authors would like to thank Dr. Michael Miller in the Auburn University Research Instrumentation Facility, Dr. Bart Prorok in the Auburn University Materials Engineering Research Center, and Brian Schweiker in the Department of Chemical Engineering for his technical assistance.

Supplementary material

11051_2013_2089_MOESM1_ESM.docx (735 kb)
Online Resource 1: TEM images and corresponding histograms are available for the Co nanoparticles stabilized by the functional solvent, DMSO, for each of the different reagent ratios of [Co2+]:[NaBH4] 4:1, 4:3, 4:5, 4:6, 4:7, 4:9. This material is available free of charge at (DOCX 735 kb)
11051_2013_2089_MOESM2_ESM.docx (150 kb)
Online Resource 2: Size histograms from TEM analysis for Co nanoparticles synthesized in DMSO when a) exposed to environmental air during synthesis, b) purged with air during synthesis, c) exposed to air for 4.5 days after synthesis, d) purged with air for 4.5 days after synthesis. This material is available free of charge at (DOCX 151 kb)


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Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Jennifer N. Duggan
    • 1
  • Michael J. Bozack
    • 2
  • Christopher B. Roberts
    • 1
  1. 1.Department of Chemical EngineeringAuburn UniversityAuburnUSA
  2. 2.Department of PhysicsAuburn UniversityAuburnUSA

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