Hydrogen activation of spectroscopic graphite surface by argon plasma etching

Abstract

Argon plasma bombardment was successfully used for the hydrogen activation of spectroscopic graphite electrodes. The hydrogen evolution reaction (HER) in 1m KOH was investigated using electrochemical techniques such as galvanostatic polarization and a.c. impedence spectroscopy; the electrode surface was characterized by SEM. It is shown that the rate of HER at a given hydrogen overpotential value increases exponentially with the etching time (ET), up to ETs of 30min, and slightly decreases from 30 to 60min. The double-layer capacity (Cdl) was established against the hydrogen overpotential for different ETs, with Cdl reaching its maximum for ETs of 30min. Moreover, it is shown that the etching process also leads to a significant increase in intrinsic activity toward HER.