The rate of the last two reactions differs to a great extent, resulting
in anodic currents which differ mutually for even one order of
magnitude (Fig. 2). In the cyclic voltammetry experiments in acidic
solution, upon the reversal of anodic to cathodic direction of polarization,
the current dropped to the values close to zero, indicating
passivation of the surface [41]. In the alkaline solutions, upon the
reversal to cathodic direction of polarization, nearly constant current
was observed indicating fast dissolution of electroformed
tungsten-oxide.