ИСТИНА

Ionic liquids (ILs) attract increasing attention worldwide because they promise significant environmental benefits. ILs are potentially important green solvents due to their non-flammability and low vapor pressure. Because of ILs’ excellent properties such as good ionic conductivity, wide electrochemical potential window, high electrochemical and thermal stability, they are widely used in electrochemistry. In this field ILs are under investigation as solvents for technological applications such as metal surface finishing, batteries, capacitors, fuel cells, electrosynthesis. Metal copper is known to be widely used in industry, power generation and transmission, electronic product manufacturing. For example, copper is of intensive use as a current collector in lithium-ion secondary batteries. So, the research of the electrochemical behavior of copper in ILs keeps on drawing a great attention. In the current work, the anodic behavior of copper in ILs based on the imidazolium cation was investigated using electrochemical measurements, microscopic observations, and gravimetric analyses. The anodic dissolution of copper was carried out in two ILs: hydrophilic BMImCl (1-butyl-3-methylimidazolium chloride) and hydrophobic BMImNTf2 (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) under aerobic conditions at room temperature. The mass loss of the copper anode upon galvanostatic polarization is evident to follow the Faraday’s law in both cases. In the case of BMImCl, the slope of the plot of the mass loss of copper vs. the quantity of electricity corresponds to the electrochemical equivalent of copper equal to 0.6588 mg/C and is consistent with the half-reaction Cu0 – 1e → Cu+. The interesting data were obtained during the electrochemical dissolution of copper in hydrophobic BMImNTf2. The experimental plots of the mass loss of copper were obtained for IL containing different concentration of water. The increase in the concentration of water in BMImNTf2 surprisingly results in the reproducible decrease in the rate of copper dissolution. The effective constant was found to depend on the water concentration. The inhibition effect of water in hydrophobic IL was proved by the data of the cyclic voltammograms and of the standard polarization measurements. The measurements are complemented by scanning electron microscopy.