ELECTROCHEMICAL PROPERTIES OF VARIOUS CARBON MATERIALS. CALCULATION OF OXYGEN ADSORPTION
Abstract
New carbon materials such as oxidized (OG) and thermally expanded (TEG) graphite modified with salts of transition metals have been applied in chemical power sources (CPS) as a catalyst. An optimal combination of properties of the porous structure and chemical composition of the surface allows creating high power adsorption system. Particular attention is paid to the system of oxygen storage, widely used in various fields of human activity. The electrocatalytic activity and electrochemical properties of various carbon materials modified with salts of cobalt and iron were studied by cyclic voltammetry in alkaline solution. Working electrode polarization modes are set using the potentiostat and the PC with the interface unit. The current-voltage graphs were obtained on a personal computer with advanced signal processing on the interface device. The relative error does not exceed 3% at the determination of the redox potential values. The potentials were recorded for the observed processes with an accuracy of ± 0.01. The Randles – Shevchik equation was used to calculate the number of electrons in order to clarify the mechanism of electroreduction process in a flow of molecular oxygen (2 or 4). To assess the effect of electrocatalisis not only high current density can be used, but also the half-wave potential of the reduction of molecular oxygen. On the cathode side of the graph with the introduction of oxygen into the electrolyte there is a significant increase in current at the potential range from -0.2 to -0.6 V and from -0.7 to -0.9 V the increase in current occurs due to a process of electroreduction of molecular oxygen. Quantified characteristics of adsorption of molecular oxygen, such as the maximum amount of adsorption and Langmuir adsorption coefficient were determined based on the electrochemical properties. Langmuir adsorption coefficient characterizes the interaction energy of the adsorbate with the adsorbent. The data obtained can be used for further research cathodes with air (oxygen) depolarization.
For citation:
Filimonov D.A., Yudina T.F., Bazanov M.I., Bratkov I.V., Leontiev N.A. Electrochemical properties of various carbon materials. Calculation of oxygen adsorption. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 2. P. 20-25.
References
Dyadin Yu.A. Graphite and its inclusion compounds. Soros Educational Journal. 2000. V. 6. N 10. P. 43-49 (in Russian).
Popova O.V., Popova S.S., Ol'shanskaya L.N. Prospects for using artificial graphite produced from lignin in electrodes of chemical power cells. J. Appl. Chem. 2008. V. 81. N 5. P. 786-791. DOI: 10.1134/s107042720805011x.
Bobrinskaya E.V., Vvedenskiy A.V., Krashchenko T.G. The adsorption of oxygen and electrocatalysis on gold in alkaline environment: state of the problem. Kondensirovannye sredy i mezhfaznye gratitsy. 2014. V. 16. N 4. Р. 381-405 (in Russian).
Gubkinа M.L., Vartapetyan R.Sh., Voloshchuk A.M., Cartel N.T. The adsorption of oxygen on carbon oxygen sensors ac-cording to gas chromatography. Struktura i dynamika molekularnykh sistem. 2003. V. 10. N 3. Р. 10-16 (in Russian).
Yudina T.F., Bratkov I.V., Ershova T.V., Smirnov N.N., Beiylina N.Yu., Mayanov E.P. Conditions optimization of natural graphite oxidation. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2014. V. 57. N 5. P. 11-13 (in Russian).
Filimonov D.A., Yudina T.F., Bratkov I.V., Bazanov M.I., Ershova T.V. Cyclic voltammetry method for study of oxidized graphite in alkaline solution. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2015. V. 58. N 1. P. 109-112 (in Russian).
Filimonov D.A., Bazanov M.I., Yudina T.F., Ershova T.V., Shchennikov D.V. Electrochemical investigations of thermal expanded graphite in alkaline medium. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2014. V. 57. N 4.
P. 10-13 (in Russian).
Filimonov D.A., Yudina T.F., Bratkov I.V., Ershova T.V. Method of cyclic voltammetry for electrochemical studies of graphite materials in alkaline medium. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2016. V. 59. N 2.
P. 60-63 (in Russian).
Filimonov D.A., Yudina T.F., Bratkov I.V., Leontiev N.A., Ershova T.V. Thermally expanded graphite and oxidized graph-ite modified with transition metal salts: electrochemical properties. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2016. V. 59. N 3. P. 55-59 (in Russian).
Antropov L.I. Theoretical electrochemistry. M.: Vysh. Shkola. 1984. 519 p. (in Russian).
Kravtsov V.I., Krasikov B.S., Tsventarny E.G. Guide to practical work on the electrochemistry. L.: Leningrad State Universi-ty. 1979. 216 p. (in Russian).
Maiyranovskiy V.G. Electrochemistry of porphyrins. In: Porphyrins: Spectroscopy, Electrochemistry, Applications. M.: Nauka. 1987. P. 127-181 (in Russian).
Galus Z. Theoretical fundamentals of electrochemical analysis. M.: Mir. 1974. 552 p. (in Russian).
Tarasevich M.R. Electrochemistry of carbon materialov. M.: Nauka. 1984. 253 p. (in Russian).
Bazanov M.I., Berezina N.M., Karimov D.R., Berezin D.B. Electrochemical and Electrocatalytic Properties of meso-Triphenylcorrole and its Complexes with Mn(III), Co(III), Cu(III) and Zn(II). Elektrokhimiya. 2012. V. 48. N 9. P. 905–910 (in Russian).
