Cobalt nanoparticles prepared by three different methods |
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Authors: | Andréia Soares Zola Renata Uema Ribeiro José Maria Correa Bueno Daniela Zanchet |
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Affiliation: | 1. Chemical Engineering Department , State University of Maringá (UEM) , Colombo Av. 5790, 87020-900 Maringá , PR , Brazil;2. Chemical Engineering Department , Federal University of S?o Carlos (UFSCar) , PO Box 676, 13565-905 S?o Carlos , SP , Brazil;3. Inorganic Chemistry Department , State University of Campinas (UNICAMP) , PO Box 6154, 13083-970 Campinas , SP , Brazil |
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Abstract: | This work aimed to study cobalt nanoparticles (Co-NPs) preparation using three different methods in order to evaluate the effect of synthesis variables that can influence the nanoparticle size distribution and particle shape. The synthesised nanoparticles were characterised by Transmission Electron Microscopy. The first synthesis employed decomposition of Co2(CO)8, at high temperatures. This procedure resulted in spherical nanoparticles with low size distribution. The size of Co-NPs could be tuned by modification of precursor/surfactant, nevertheless the stirring and injection time influenced the size distribution. Using polyol process, at high temperatures, it was produced undefined-shape nanoparticles. This result suggests that the solution composition, i.e. the amount of trioctylphosphine and oleic acid was not suitable to control both size and shape of nanoparticles. Finally, the method based on reduction with NaBH4 resulted spherical nanoparticles with tiny sizes, indicating that in this case a variation on amount of reductant would be more efficient on the particle size control than a variation in concentration of oleic acid. These results indicated that, for each method, a different variable exists for the control of the distribution size and the shape of the formed particles. |
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Keywords: | cobalt nanoparticle size control particle size distribution synthesis |
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