Preparation and characterization of cobalt oxide nanosized particles obtained by an electrochemical method (original) (raw)
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Study of influential factors in synthesis and characterization of cobalt oxide nanoparticles
Journal of Nanostructure in Chemistry, 2013
This study has investigated the different factors in obtaining cobalt oxide nanoparticles. The factors that have been studied are the effect of pH, synthesis temperature, capping agent, annealing temperature, and different usage of cobalt salts. Cobalt oxide nanoparticles were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, UV, Fourier transform infrared spectroscopy, and X-ray diffraction. In order to find the effects of various factors, the optimum pH was achieved in the first experiment by the precipitation method; after finding out that in experiments with pH 8 to 9, the particles are homogeneous in shape and regular. The other experiments were repeated with the same pH but changing the factors. In the second experiment, the effect of synthesis temperature at 40°C, 60°C, 80°C, and 100°C was investigated. To find out the effect of capping agent, two experiments were done, one using the oleic acid and the other using 2-(dodecyloxy) acetic acid. In the case of investigating the annealing temperature, the black cobalt oxides were annealed at 400°C, 500°C, and 600°C. The last one was done using two different cobalt salts, cobalt nitrate and cobalt sulfate. Finally, cobalt oxide nanoparticles were characterized.
Effect of Solvents on Synthesis and Characterization of Cobalt Oxide ( Co 3 O 4 ) Nanoparticles
We report characteristic of cobalt oxide (Co3O4) nanoparticles prepared by thermal decomposition of Co (Ac)2·4H2O using oleic acid capping agent and NaBH4 reducing agent. Variable in this study is types of solvent: acetone (S1), hexane (S2), and xylene (S3). Physical and chemical properties of the as-prepared Co3O4 samples were investigated by TGA, TEM, BET, XRD, and FT-IR. The form of colloidal suspension using xylene and hexane were well observed. Adding NaBH4 solution, consequently, the pinkviolet solution using these two solvents turned into black due to the oxidation reaction. From XRD result, crystalline structure of Co3O4 nanoparticles prepared by using the three solvent types show the same result indicated as cubic structure with Fd-3m symmetry group and space lattice of 8.06 Å. The particle size of 82.29, 26.83 and 20.59 nm and specific surface area of 7.04, 21.28, and 32.07 m 2 /g were observed for S1, S2, and S3 sample, respectively. In addition, secondary phases were als...
Pulsed Current Electrochemical Synthesis of Co3O4 Nanostructures
2015
This paper is going to describes pulse electrosynthesis of different types of nanostructures of cobalt oxide (Co3O4), and provides a detailed analysis of the various factors affecting the morphology, narrowest size distribution and yield. Used the"one at a time" method for investigating and optimized the best result by changing the amount of all experimental effect parameters such as concentration of lithium hydroxide and potassium chloride, type and concentration of additive, bath temperature, values of ton and t off and pulse height (current amount). The morphology and particle size of each synthesized sample were investigated by using Energy scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray diffraction techniques (XRD). The optimum experimental conditions to synthesize cobalt oxide nanorods include lithium hydroxide (0.01 M), potassium chloride (0.1 M), pulsed current of 40 mA.cm -2 , pulse time(ton) of 0.5 s, relaxation time (toff) of...
Preparation and characterization of cobalt oxide nanoparticles via solution combustion method
Nano Science and Nano Technology An Indian Journal, 2009
The spherical shaped Co3O4 nanoparticles have interesting properties and potential applications in coatings, catalysis, sensors, anode materials in rechargeable batteries, solar energy absorbers, magnetism, etc. Inorganic nanoparticles with controlled size and shape are technologically important due to the strong correlation between these parameters and their properties. We have successfully prepared Co3O4 using a solution combustion method. The phase and purity of the synthesized product was examined by X-ray diffraction (XRD) pattern. Infrared spectroscopy studies were performed aiming to ascertain the metal oxygen bonding and nature of the synthesized cobalt oxide nanoparticles. SEM (Scanning electron microscope images show that the nanoparticles are nearly spherical in morphology and are in the range of 100 to 200 nm.Magnetic property and thermal behavior of the synthesized Co3O4 nanoparticles were studied by magnetic hysteresis loop tracer.
Synthesis and characterization of cobalt oxide nanoparticles by thermal treatment process
Inorganica Chimica Acta, 2009
The simple preparation of Co 3 O 4 nanoparticles from a solid organometallic molecular precursor N-N 0bis(salicylaldehyde)-1,2-phenylenediimino cobalt(II); Co(salophen) has been achieved via two simple steps: firstly, the Co(salophen) precursor was precipitated from the reaction of cobalt(II) acetate and N-N 0 -bis(salicylaldehyde)-1,2-phenylenediimino; H 2 salophen; in propanol under nitrogen condition; then, cubic phase Co 3 O 4 nanoparticles with the size of mostly 30-50 nm could be produced by thermal treatment of the Co(salophen) in air at 773 K for 5 h. The as-synthesized products were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and scanning electronic microscopy (SEM). These results confirm that the resulting oxide was pure single-crystalline Co 3 O 4 nanoparticles. The optical property test indicates that the absorption peak of the nanoparticles shifts towards short wavelength, and the blue shift phenomenon might be ascribed to the quantum effect. The hysteresis loops of the obtained samples reveal the ferromagnetic behaviors the enhanced coercivity (H c ) and decreased saturation magnetization (M s ) in contrast to their respective bulk materials.
Solution synthesis of nanometric layered cobalt oxides for electrochemical applications
Electrochimica Acta, 2012
Dispersed Na 0.6 CoO 2 ·yH 2 O and Li 0.5 CoO 2 powders have been obtained at room temperature by rapid precipitation in aqueous solutions of LiOH or NaOH in the presence of a strong oxidizer. The precipitates are well crystallized and consist of nanoscale platelets with high specific area (above 100 m 2 /g). The Li 0.5 CoO 2 phase is stable in aqueous electrolytes whereas the Na 0.6 CoO 2 ·yH 2 O rapidly converts to CoOOH in neutral electrolytes or pure water. It also transforms to anhydrous Na 0.6 CoO 2 upon drying at moderate temperatures. Electrochemical studies show that at slow sweep rates the Na 0.6 CoO 2 ·yH 2 O can store large amounts of charge in 10 M NaOH from a combination of both faradic and capacitive reactions.
Materials Letters, 2013
Co 3 O 4 nanowire, nanoparticle network, and Co 3 O 4 /graphite nanocomposite were synthesized via a hydrothermal route accompanied with a post-annealing step. The Co 3 O 4 nanowire was formed without adding graphite; after introducing graphite, the morphology of the Co 3 O 4 nanocomposite changed to a network through the partial overlapping of nanoparticles. The electrochemical properties of the samples were studied as anode materials in lithium-ion batteries. The Co 3 O 4 /graphite nanocomposite outperforms two different pure Co 3 O 4 samples by showing superior Li-battery performance with dramatically enhanced cyclic performance at a current density of 500 mA/g and excellent rate performance. Its reversible capacity remains as high as 551 mA h/g after 50th cycle.
Fabrication and Characterization of Nanoporous Co Oxide (Co3O4) Prepared by Simple Sol-gel Synthesis
Physical Chemistry Research, 2016
Cobalt oxide (Co 3 O 4) nanorods were prepared by a simple co-precipitation method using ethanol solution of cobalt nitrate as precursor and cetyl trimethylammonium bromide (CTAB) as surfactant. Morphological properties of the nanoparticles were characterized. XRD measurement exhibited the structure of Co 3 O 4 nanocrystals for annealed samples. The SEM images revealed that the particles changed from spherical shape to rod-like shaped by increasing annealing temperature. The TEM results exhibited that the size of cobalt oxide nanoparicles decreased from 25 nm for as-made particles to 50 nm for annealed samples with increasing temperature. The FTIR analysis confirmed the functional group presents in the cobalt oxide nanoparticles. The sharp peaks in FTIR spectrum determined the purity of Co 3 O 4 nanoparticles and existence of CoO group. Absorbance peak of UV-Vis spectrum showed the band gap energy of 3.69 eV corresponding to wavelength about 335 nm for as-prepared samples and the band gap energy of 3.49 eV corresponding to wavelength about 355 nm for annealed Co 3 O 4 nanoparticles. The results of magnetic measurements indicated a good coercive field and saturation magnetism around 447.81 G and 17.295 emu g-1 , respectively.