Theoretical Study on Adsorption of 8-hydroxyquinoline Inhibitor on Magnesium Surface
8-hydroxyquinoline(8HQ)is a common corrosion inhibitor used for surface corrosion protection of magnesium alloys.In order to theoretically explore its mechanism,quantum chemical calculations were performed using Density Functional Theory(DFT).The structure and properties(bond lengths,bond angles,charges,infrared spectra,thermodynamic properties,reaction activity,and stability)of the 8HQ molecule and its adsorption on the Mg(001)surface were analyzed using the Dmol3 program.The results show that through the calculation of bond length and bond angle,the C—N bond length is shorter,suggesting that the C—N bond in the quinoline ring is more difficult to break.The distribution of frontier orbital density of the corrosion inhibitor molecule is mainly on the N atom and the hydroxyl group connected to the quinoline ring,as well as on the C atom,which can predict that the main adsorption reaction site of the corrosion inhibitor molecule on the metal surface is at this location.Through the analysis of the vibrational spectrum of 8HQ by infrared spectroscopy and thermodynamic properties at different temperatures,it was found that there is functional relationship between the thermodynamic properties such as gas heat capacity,entropy,and enthalpy of the molecule and temperature.The adsorption energy of the 8HQ on the Mg(001)surface confirmed that the adsorption sites are mainly N,O atoms and the adsorption proceeds spontaneously.
8-hydroxyquinolinequantum chemistryinfrared spectrumadsorption energy
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