Plasma-chemical preparation of nanoscale cobalt oxide
DOI:
https://doi.org/10.15276/opu.1.51.2017.15Keywords:
plasma discharge, production, aqueous solutions, cobalt oxide, nanoparticlesAbstract
As of today, sols and nanodispersed systems of transition metal oxides are increasingly spreading. Due to a number of properties, undoubted interest for the development of technologies in various industries is represented by cobalt oxide Со3О4. In this paper, we demonstrate the results of studies on the use of a contact nonequilibrium low-temperature plasma as a tool for obtaining nanoscale cobalt oxide. Aim: The aim of the work is to obtain cobalt oxide using a contact nonequilibrium low-temperature plasma. Materials and Methods: The investigations were carried out in a gas-liquid batch reactor. The electrodes are made of stainless steel. The plasma column formed as a result of the test is a processing tool. Cooling of the reaction mixture was ensured by continuous circulation of cold water. The reactor pressure was 80±4 kPa. To obtain a plasma discharge, a voltage of 500...1000 V was applied to the electrodes. The current was maintained at 120±6 mA. Optical spectra of sols were recorded in the wavelength range 190...700 nm. The thermal analysis was carried out in an air medium at a heating rate of 10 deg/min in quartz crucibles. The obtained samples were examined by X-ray phase analysis. The dimensional parameters of the obtained compounds were examined using an electron microscope. Results: It was found that the final pH value of cobalt hydroxide precipitation varies in the range 8.2...9.0 and, depending on the magnitude of the ionic force, is 9.0 and 8.2 at I = 0, I = 1, respectively. The regularities of the change in the oxidation-reduction potential and the hydrogen index of cobalt oxide solutions during their processing by a low-temperature nonequilibrium plasma are studied. The phase composition of the plasma-chemical obtained cobalt compounds was investigated by X-ray diffraction and thermal analysis. The main phase of the product obtained is represented by cobalt oxide of structure Со3О4. According to the data of microscopic and X-ray diffraction methods of analysis, it is shown that the sizes of the obtained cobalt compounds lie in the nanometer range.
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