ORALS

SESSION: ElectrochemistryWedPM1-R2	Amatore International Symposium on Electrochemistry for Sustainable Development
Wed Nov, 7 2018 / Room: Copacabana B (150/1st)
Session Chairs: Dongping Zhan; Session Monitor: TBA

14:00: [ElectrochemistryWedPM105]
Electrochemical Behavior of Boron-doped Synthetic Diamond Compacts - A New Electrode Material
Yuri Pleskov¹ ; Marina Krotova² ; Eugeniy Ekimov³ ; ¹Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russian Federation; ²1FRUMKIN INSTITUTE OF PHYSICAL CHEMISTRY AND ELECTROCHEMISTRY, Moscow, Russian Federation; ³INSTITUTE FOR HIGH PRESSURE PHYSICS, Moscow, Russian Federation;
Paper Id: 81 [Abstract]

Traditional thin-film synthetic diamond electrodes produced by chemical-vapor deposition (CVD, see [1, 2]) are remarkable for their wide potential window and low background current in supporting electrolytes and good reproducibility. However, they are not free of disadvantages, particularly from the film exfoliation from substrate, thru-holes, etc. In this work we presented a new electrode material, heavily boron-doped diamond compacts whose electrochemical properties are studied for the first time. Cylinder-shaped polycrystalline samples, 3.5-4 mm in diameter and 2.5 mm in height, were prepared by thermobaric processing of graphite-boron carbide mixtures at the pressure of 8-9 GPa and temperature of ~2500 K [3]. Their diamond nature, in particular, the absence of graphite, was confirmed by Raman spectroscopy and XRD technique. Their electrode behavior is studied by using cyclic voltammetry and electrochemical impedance spectroscopy. The compacts are shown to be superior to conventional thin-film CVD-diamond electrodes in their electrode characteristics. In particular, they have wide potential window, low background current in indifferent electrolytes (KCl, K₂SO₄), and good reproducibility. Moreover, their extremely high doping level makes them more electroactive, as can be seen by the current of Cl₂ anodic evolution from KCl solutions (figure), some organics electrooxidation, etc. [4]. Thus, the diamond compacts are well comparable to the CVD-diamond electrodes. At the same time, they are free of some drawbacks inherent in the latter. Moreover, their concentrated form can be advantageous in the designing of electrochemical devices. One might think that they can successfully be used, e.g., as electrodes in electrosynthesis, electroanalysis, water treatment, etc. [5].

References:
[1] Yu.V. Pleskov, A.Ya. Sakharova, M.D. Krotova, L.L. Bouilov, B.V. Spitsyn, J. Electroanal. Chem. 228 (1987) 19-27.
[2] Synthetic Diamond Films: Preparation, Electrochemistry, Characterization and Applications, Brillas, E. and Martinez-Huitle, C.A., Eds., New York: Wiley, 2011.
[3] E.A. Ekimov, V. Ralchenko, A. Popovich, Diamond Related Mater. 50 (2014) 15-19.
[4] Yu.V. Pleskov, M.D. Krotova, V.V. Elkin, E.A. Ekimov, Russ. J. Electrochem. 52 (2016) 3-9.
[5] Yu.V. Pleskov, M.D. Krotova, V.V. Elkin, E.A. Ekimov, Electrochim. Acta 201 (2016) 268-273.