Separation and kinetic study of iron corrosion in acidic solution via a modified tip generation/substrate collection mode by SECM

Highlights: • A modified TG/SC mode of SECM to be used in electrochemistry corrosion field. • The net Fe oxidation and proton reduction current can be separated and quantified. • Obtaining kinetic parameters and transfer coefficients of both anodic and cathodic reaction during Fe corrosion process. • Obtaining more accurate corrosion current in time than the traditional electrochemical method. - Abstract: Anodic dissolution and cathodic hydrogen evolution behavior of pure Fe in 5 mM HClO₄ solution was investigated via a modified tip generation/substrate collection mode using scanning electrochemical microscopy. The modified TG/SC mode of SECM could instantaneously divide the apparent current of Fe corrosion process into Fe oxidation and proton reduction process, and standard rate constants and transfer coefficients of hydrogen evolution and Fe oxidation are 9.2 × 10⁻⁶ cm/s and 0.27, 2.5 × 10⁻⁶ cm/s and 0.7, respectively, based on COMSOL simulation and Tafel linear fitting. Comparing with traditional polarization curve and electrochemical noise, the more accuracy corrosion current can be obtained in time.