Unravelling the mechanisms of corrosion inhibition of iron by henna extract: A density functional theory study

摘要

The corrosion inhibition effect of the three main constituents in henna extract: lawsone, gallic acid and alpha-D-glucose, on the Fe (001) surface was studied using density functional theory. Quantum chemical descriptors as well as the interaction energies predict their corrosion inhibition efficiencies to follow the trend: lawsone gallic acid alpha-D glucose consistent with experiments. Lawsone and gallic acid were found to strongly chemisorb on the surface through formation of O-Fe or C-Fe bonds while the interactions of alpha-D glucose with the surface are rather weak as steric effects preclude ring C and O interactions with surface Fe-atoms.