Journal of Applied Electrochemistry, Vol.28, No.6, 601-606, 1998
Hydrogen activation of spectroscopic graphite surface by argon plasma etching
Argon plasma bombardment was successfully used for the hydrogen activation of spectroscopic graphite electrodes. The hydrogen evolution reaction (HER) in 1 M 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 30 min, and slightly decreases from 30 to 60 min. The double-layer capacity (C-dl) was established against the hydrogen overpotential for different ETs, with C-dl reaching its maximum for ETs of 30 min. Moreover, it is shown that the etching process also leads to a significant increase in intrinsic activity toward HER.
Keywords:GLASSY-CARBON ELECTRODES;SCANNING TUNNELING MICROSCOPE;EVOLUTION REACTION;KINETICS;IMPEDANCE