ИСТИНА

Nanoparticles attract much attention in different fields of science and nanotechnologies due to their excellent physical and chemical properties. Nanoparticles are defined as solid particles of up to 100 nm in size [GOST R 55416-2013]. Active forms of metal oxide nanoparticles that are obtained electrochemically, especially titanium oxide (IV), have a highly-developed surface and can be used as catalyst electrodes. Among various methods of synthesis of metal nanooxides, the synthesis in ionic liquids gets special attention – as promising replacement of traditional solvents. The further development and use of ionic liquids for production of nanomaterials is a future trend for nanotechnologies. There have been two stages of the research. The first stage consisted of anodic oxidation of titanium and nickel electrodes in the ionic liquid, adding distilled water or propylene glykol. The second stage was the study of electrocatalytic properties of synthesized nanostructures in electrochemical reduction of СО2 in ionic liquids. At the first stage titanic and nickel catalyst electrodes have been obtained due to the electrochemical treatment; these electrodes have been modified by nanosized particles of titanium oxide (IV) and nickel oxide (II) respectively. For the synthesis of nanostructures of titanium dioxide TiO2 and nickel oxide NiO the following ionic liquids have been used – on the base of imidazolium cation as electrolyte and stabilizer (bis(trifluorine-methyl sulfonyl)imid 1-butyl-3-methylimidazolium (BmimNTf2) and chloride 1-butyl-3-methylimidazolium (BmimCl)). Such ionic liquids are not flammable and also remain stable in a wide temperature range (up to 400°C). They are also characterized by big “windows” of electrochemical stability (from –2 up to +2 В, relative to potential of chloride-silver electrode). At the same time they function as a medium that forms and stabilizes the nanoparticles of metal oxides. Exposure time varied from 1 to 30 minutes, with 1-10 mA DС or constant potential 1-10 V in the air. At the second stage the nanosized titanium and nickel oxides have been studied; these oxides have been synthesized under electro-catalyst conversion СО2 in ionic liquids under various cathode potential and exposure time. Electrochemical behavior of СО2 have been studied in BmimNTf2 and 1-butyl-3-methylimidazolium tetrafluoroborate (BmimBF4) ionic liquids. The studied ionic liquids dissolve CO2 well; that was confirmed by the method of cyclic voltammetry. The selected modes have also been tested on the carbon nanotubes (CNTs) in the Ilmenau University of Technology. As a result of the conducted research the conditions for the one-stage synthesis of applied nanosized structures of nickel and titanium oxides in ionic liquids have been determined. The suggested method allows to obtain the nanoparticles of metal oxides as 0D or 1D structures – depending on synthesis conditions. As a result of electrochemical reduction of СО2 in ionic liquids with anode the light-green sediment forms in the solution out of NiO; based on the data of chemical analysis this sediment corresponds to the insoluble nickel oxalate.