HYDROGEN ACTIVATION OF SPECTROSCOPIC GRAPHITE SURFACE BY ARGON PLASMA-ETCHING

Argon plasma bombardment was successfully used for the hydrogen activa tion of spectroscopic graphite electrodes. The hydrogen evolution reac tion (HER) in 1 M KOH was investigated using electrochemical technique s such as galvanostatic polarization and a.c. impedence spectroscopy; the electrode surface was characterized by SEM. It is shown that the r ate of HER at a given hydrogen overpotential value increases exponenti ally with the etching time (ET), up to ETs of 30 min, and slightly dec reases from 30 to 60 min. The double-layer capacity (C-dl) was establi shed against the hydrogen overpotential for different ETs, with C-dl r eaching its maximum for ETs of 30 min. Moreover, it is shown that the etching process also leads to a significant increase in intrinsic acti vity toward HER.