Electrochemical and Photoelectrochemical Study of Self‐assembled Monolayer of Phytic Acid on Brass

Phytic acid is an environment‐friendly reagent for processing metals. The anticorrosion and inhibiting mechanism for phytic acid monolayers self‐assembled on a brass (HSn70‐1) electrode has been investigated by using electrochemical and photocurrent response methods. The electrochemical measurements indicate that phytic acid is liable to form surface complexes on the brass electrode, and the self‐assembled monolayers (SAM) change the structure of the electric double‐layer and shift the potential of zero charge positively. The photochemical measurement indicates that the brass electrode shows a p‐type photoresponse owing to the formation of a Cu₂O layer on its surface, and the presence of SAM weakens significantly the photoresponse, suggesting an excellent effect on anticorrosion, which is consistent with the EIS and polarization curve measurements. Adsorption of phytic acid was found to be typical of chemisorption, which can be reasonably described on the basis of the Langmuir isotherm.