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- Title
СИНТЕЗ, СТРУКТУРА ТА ЕЛЕКТРОХІМІЧНІ ВЛАСТИВОСТІ УЛЬТРАДИСПЕРСНОГО АМОРФНОГО β-FeOOH
- Authors
Груб'як, А. Б.; Коцюбинський, В. О.; Мохнацька, Л. В.; Мокляк, В. В.; Колковський, П. І.; Мудрик, Г. І.
- Abstract
The aim of the article is to find relationships between synthesis conditions and phase composition, magnetic microstructure and electrochemical properties of ultrafine amorphous iron hydroxide phases obtained by iron citrate sol hydrothermal treatment. The sol of iron citrate was formed by mixing of 0.3 M iron nitrate aqueous solutions with citric acid. Hydrothermal treatment of iron citrate was carried out at 120 °C for 5 hours with the next annealing of precipitation at 150, 200, 250, 300 and 350 °C in air for 2 hours. X-ray analysis and Mössbauer spectroscopy were used for phase composition and magnetic microstructure control of the obtained iron hydroxides. All the synthesized materials were X-ray amorphous so the Mössbauer spectroscopy was used for phases recognition. In has been determined that the hydrothermal treatment of iron citrate solution at 120 °C for 5 hours leads to Fe(OH)3 formation. The annealing in the temperature range of 150-200 °C causes the reduction of iron Fe3+→Fe2+ as a result of material dehydration. Under this condition the composite Fe(OH)3/ Fe(OH)2 was formed with the pentahydrate iron citrate C6H5O7Fe⋅5H2O and iron oxalate FeC2O4·2H2O presence. Amorphous ultrafine β-FeOOH was obtained after Fe(OH)3 annealing at 250 °C for 2 hours. It has been found that after annealing at 350 °C phase transformation of β-FeOOH→α-Fe2O3 has occurred. The sizes of coherent scattering regions for α-Fe2O3 phase are about 15.0±1.5 nm. The electrochemical properties of ultrafine amorphous β-FeOOH and composite β-FeOOH/carbon nanotubes in 3.5M KOH aqueous solution were studied. The efficiency of β-FeOOH/carbon nanotube as potential electrode material for supercapacitor was shown.
- Publication
Chemistry, Physics & Technology of Surface / Khimiya, Fizyka ta Tekhnologiya Poverhni, 2016, Vol 7, Issue 3, p300
- ISSN
2079-1704
- Publication type
Academic Journal
- DOI
10.15407/hftp07.03.300