The effect of cathodic polarization on the electrochemical behavior of the thin titanium
dioxide film formed by anodic pretreatment over pure commercial titanium metal for
biomaterial application was investigated in situ using scanning electrochemical microscopy
(SECM). Quantitative information on the electron transfer rates (keff) at the titanium surface
was obtained using the feedback operation of SECM using ferrocene-methanol (FcMeOH) as
electrochemical mediator. An increase of keff values with the increase of the negative
polarization was detected, a feature that correlates well with the decrease of titanium oxide
resistance with increasing cathodic polarization observed using electrochemical impedance
spectroscopy (EIS). In addition, SECM operation in the redox competition mode proved that
hydrogen was absorbed in the surface oxide film leading to changes in conductivity and
electrochemical reactivity
