Compacts of Boron-Doped Synthetic Diamond - Acceleration of Cathodic Reactions by Plasma-Assisted and Electrochemical Treatment of the Electrodes
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2022-06-01 |
| Journal | Russian Journal of Electrochemistry |
| Authors | Š. Š. ŠŃŠøŠ²ŠµŠ½ŠŗŠ¾, Roman A. Manzhos, V. K. Kochergin, Š. Š”. ŠŠ¾ŃŠŗŠøŠ½, Yu. V. Pleskov |
| Institutions | Institute of Problems of Chemical Physics, Frumkin Institute of Physical Chemistry and Electrochemistry |
| Citations | 2 |
Abstract
Section titled āAbstractāDiamond compacts were synthesized by thermobaric processing of graphite and amorphous boron mixtures under the conditions of the diamond thermodynamic stability (at a pressure of 8-9 GPa and temperature of ā¼2500 K). The boron-doped diamond-compact electrode surface was modified by its subjecting to the action of cathodic, anodic, and cathodic-anodic electrolytic plasma formed under the applying of voltage pulses with amplitude up to 300 V in Na2SO4 aqueous solution. It was found by using rotating disc electrode that the applying of sole cathodic-anodic plasma provides negligible catalytic effect with respect to the oxygen reduction reaction. However, thus pre-processed electrode acquired significant electrocatalytical activity upon the cathodic treatment, with the consequence that the reaction of O2 reduction to H2O passed predominantly by the four-electron mechanism. At the same time, the cathodic polarization of the plasma-modified electrode produced no effect on the rate constant of the electron transfer in the [Ru(NH3)6]2+/3+ redox couple; yet, the rate constant in the [Fe(CN)6]4-/3- one increased significantly. Hypothetically, the observed electrocatalytical effect in the oxygen reduction reaction is due to the formation, under the combined action of the cathodic-anodic plasma and cathodic polarization, of quinone groups at the boron-doped diamond surface; they play the role of active sites for the oxygen four-electron reduction.