| Abstract: | The adsorption and kinetic processes of the formation of gas bubbles passivating the surface during polarization of copper
and graphite electrodes in 1% aqueous solution of sulfuric acid have been investigated. Three stages of the process related
to the recharging of the double electric layer—adsorption accumulation of the gas escaping from the surface, the critical
nucleation of the gas bubbles, and their subsequent growth—have been revealed, distinguished, and quantitatively estimated.
It has been shown that potential leveling at the steady-state value specified by the Tafel equation is unambiguously associated
with achievement of the limiting surface area screened by the gas bubbles for each particular current density. The surface
diffusion constants D
H = (1.5–4.4) × 10−4 and (0.1–3.8) × 10−5 cm2/s of hydrogen on copper and graphite, respectively, and D
O = (1.8–4.5) × 10−7 cm2/s of oxygen on graphite during the motion toward the drain (the gas bubbles) have been calculated. |
