Effect of Anions on the Anodic Dissolution Behavior of Iron: An Electrochemical and Density Functional Theory Study

The influences of SO42−, Cl−, ClO4− and BF4− on the corrosion behavior of Fe in acidic solutions were quantitatively investigated through macro- and micro-electrochemical techniques, combined with DFT calculation. The electrochemical results showed that the corrosion rate increased in the order of BF4−, ClO4−, Cl− and SO42−, confirmed by the negative shift of OCP and Ecorr, the decrease of Rct and the increase of keff of Fe oxidation. DFT calculation showed that the adsorption of SO42− on Fe(100) surface was easier and stronger than Cl−, and caused more significant Fe surface structure changes, resulting in more serious corrosion of Fe.