Multiscale electrochemical analysis of the corrosion control of bronze in simulated acid rain by horse-chestnut (Aesculus hippocastanum L.) extract as green inhibitor

Horse-chestnut ethanolic extract was tested as potential corrosion inhibitor of bronze in simulated acid rain. The extract was analysed by FTIR, GC-MS and HPLC-PDA, and its anti-corrosion behaviour studied using a multiscale electrochemical approach by polarization curves, EIS and scanning electrochemical microscopy, along with SEM-EDS. 94 % inhibition efficiency was attained by developing a surface physisorbed film. A novel methodology for kinetic evaluation of dynamic adsorption of inhibitive species on metal surface is proposed using SECM, achieving good agreement with results from conventional electrochemical techniques. Excellent adsorption-desorption kinetic constants (k(a) = 0.102 s(-1) mol(-1) L; k(d) = 3.33 x 10(-5) s(-1)) were determined.