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Study on Synergistic Mechanism of Inhibitor Mixture Based on Electron Transfer Behavior

View Article: PubMed Central - PubMed

ABSTRACT

Mixing is an important method to improve the performance of surfactants due to their synergistic effect. The changes in bonding interaction and adsorption structure of IM and OP molecules before and after co-adsorbed on Fe(001) surface is calculated by DFTB+ method. It is found that mixture enable the inhibitor molecules with higher EHOMO donate more electrons while the inhibitor molecules with lower ELUMO accept more electrons, which strengthens the bonding interaction of both inhibitor agent and inhibitor additive with metal surface. Meanwhile, water molecules in the compact layer of double electric layer are repulsed and the charge transfer resistance during the corrosion process increases. Accordingly, the correlation between the frontier orbital (EHOMO and ELUMO of inhibitor molecules and the Fermi level of metal) and inhibition efficiency is determined. Finally, we propose a frontier orbital matching principle for the synergistic effect of inhibitors, which is verified by electrochemical experiments. This frontier orbital matching principle provides an effective quantum chemistry calculation method for the optimal selection of inhibitor mixture.

No MeSH data available.


The quantity distribution of water molecules and the distance of water concentration peaks to the metal surface.
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f5: The quantity distribution of water molecules and the distance of water concentration peaks to the metal surface.

Mentions: Figure 5 shows the distribution of water molecules along the distance from metal surface. It is seen that in blank solution (only water molecules is present), the peak of water molecule amount appears at the position about 3.33 Å from Fe surface. When OP or IM molecules are added into solution, the peak of water molecule amount appears at 3.36 Å and 3.42 Å, respectively. Furthermore, the amount of water molecules in the compact layer decreases obviously. When IM and OP molecules are present simultaneously, water molecules move further away from metal surface and the distance increases to 3.44 Å. The amount of water molecules in compact layer also further decreases. This situation indicates that the amount of water molecules in compact layer will decrease and compact layer will move away from metal surface as the adsorption interaction of OP and IM molecules on Fe surface becomes stronger.


Study on Synergistic Mechanism of Inhibitor Mixture Based on Electron Transfer Behavior
The quantity distribution of water molecules and the distance of water concentration peaks to the metal surface.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037402&req=5

f5: The quantity distribution of water molecules and the distance of water concentration peaks to the metal surface.
Mentions: Figure 5 shows the distribution of water molecules along the distance from metal surface. It is seen that in blank solution (only water molecules is present), the peak of water molecule amount appears at the position about 3.33 Å from Fe surface. When OP or IM molecules are added into solution, the peak of water molecule amount appears at 3.36 Å and 3.42 Å, respectively. Furthermore, the amount of water molecules in the compact layer decreases obviously. When IM and OP molecules are present simultaneously, water molecules move further away from metal surface and the distance increases to 3.44 Å. The amount of water molecules in compact layer also further decreases. This situation indicates that the amount of water molecules in compact layer will decrease and compact layer will move away from metal surface as the adsorption interaction of OP and IM molecules on Fe surface becomes stronger.

View Article: PubMed Central - PubMed

ABSTRACT

Mixing is an important method to improve the performance of surfactants due to their synergistic effect. The changes in bonding interaction and adsorption structure of IM and OP molecules before and after co-adsorbed on Fe(001) surface is calculated by DFTB+ method. It is found that mixture enable the inhibitor molecules with higher EHOMO donate more electrons while the inhibitor molecules with lower ELUMO accept more electrons, which strengthens the bonding interaction of both inhibitor agent and inhibitor additive with metal surface. Meanwhile, water molecules in the compact layer of double electric layer are repulsed and the charge transfer resistance during the corrosion process increases. Accordingly, the correlation between the frontier orbital (EHOMO and ELUMO of inhibitor molecules and the Fermi level of metal) and inhibition efficiency is determined. Finally, we propose a frontier orbital matching principle for the synergistic effect of inhibitors, which is verified by electrochemical experiments. This frontier orbital matching principle provides an effective quantum chemistry calculation method for the optimal selection of inhibitor mixture.

No MeSH data available.