Mass transfer in the electrochemical reduction of palladium(II) from a glycinate electrolyte

1Nikitenko, VN, 1Kublanovsky, VS
1V. I. Vernadsky Institute of General and Inorganic Chemistry of the NAS of Ukraine, Kyiv
Dopov. Nac. akad. nauk Ukr. 2018, 9:87-96
Section: Chemistry
Language: Russian
Abstract: 

The ionic composition of a glycinate electrolyte of palladation in the solution volume and in the near-cathode layer, concentration polarization, and alkalinization of the near-cathode layer are calculated within the framework of the Nernst theory, depending on the density of the polarizing current, ratio of main components, and pH0 in the solution volume. The basic forms of existence of palladium(II) ions and the ligand in the nearcathode layer of a glycinate electrolyte are found. It is shown that the electrochemically active complexes [Pd(gly)2] participate in the transition reaction. The reduction of palladium(II) from a glycinate electrolyte is described by the laws of mixed kinetics. The mechanism of electroreduction of palladium(II) from a glycinate electrolyte is proposed.

Keywords: concentration polarization, glycinate complexes of palladium(II), ionic composition of an electrolyte, mass transfer, mechanism of electroreduction, near-cathode layer
References: 
  1. Orekhova, V. V. & Andryushchenko, F. K. (1979). Polyligand electrolytes plating. Khar'kov: Vishcha shkola (in Russian).
  2. Kublanovsky, V. S. & Nikitenko, V. N. (2011). Electrochemical properties of palladium(II) trans- and cisdiglycinate complexes. Electrochim. Acta, 56, pp. 2110-2115. doi: https://doi.org/10.1016/j.electacta.2010.11.028
  3. Kyblanovsky, V. S. & Nikitenko, V. N. (2013). Mechanism of the electrodeposition of palladium coatings from glycinate electrolytes. J. Electroanal. Chem., 699, pp. 14-20. doi: https://doi.org/10.1016/j.jelechem.2013.03.021
  4. Bek, R. Yu. (1977). Peculiarities of the electrodeposition of metals from solutions with a small excess of ligand. Izv. Sib. otd. AN SSSR. Ser. him. nauk, No. 3, pp. 68-76 (in Russian).
  5. Kyblanovsky, V. S., Nikitenko, V. N. & Chornenka, N. V. (2009). Spectrophotometric and pH-potentiometric determination of the stability constants of palladium(II) glycinate complexes. Ukr. Khim. Zhurn., 75, No. 9, pp. 50-56 (in Russian).
  6. Kamke, E. (1965). Handbook of ordinary differential equations. Moscow: Nauka, 1965 (in Russian).
  7. Ibl, N., Barrada, Y. & Trumpler, G. (1954). Natural convection during electrolysis: interferometric studies of diffusion layer. Helv. Chim. Acta, 37, pp. 583-597.
  8. Bretshnaider, S. (1966). Properties of gases and liquids. Egineering calculation methods. Moscow, Leningrad: Khimiya (in Russian).
  9. Chornenka, N. V. & Nikitenko, V. N. (2006). Synthesis, identification, isomerization and electrochemical properties of trans- and cis-diglycinate complexes of palladium(II). Ukr. khim. zhurn., 72, No. 1, pp. 48-52 (in Russian).
  10. Chemical handbook (1965). Vol. 3. Chemical equilibrium and kinetics. Properties of solutions. Electrode processes. Moscow, Leningrad: Khimiya (in Russian).
  11. Damaskin, B. B., Petrii, O. A. & Tsyrlina, G. A. (2006). Electrochemistry. Moscow: Khimiya (in Russian).
  12. Nikitenko, V. N., Litovchenko, K. I. & Kublanovsky, V. S. (1981). Calculation of ionic composition and concentration polarization on the electrode surface in cadmium(II) electrodeposition from α-aminoacetic solutions. Ukr. khim. zhurn., 47, No. 4, pp. 339-344 (in Russian).
  13. Nikitenko, V. N., Litovchenko, K. I., Kublanovsky, V. S. (1998). Concentration changes in the diffusion layer during the reduction of cadmium(II) from an iminodiacetate electrolyte. Elektrochimiya, 34, No. 5, pp. 487-491 (in Russian).
  14. Kublanovsky, V. S., Gorodyskii, A. V., Belinskii, V. N. & Gluschak, T. S. (1978). Concentration changes in the near-electrode layers during electrolysis. Kiev: Naukova Dumka (in Russian).
  15. Prshibil, R. (1960). Complexones in chemical analysis. Moscow: Izd-vo inostr. lit. (in Russian).