Ectrochemistry Of Copper With New Imidazolopyridine Inhibitors Corrosion Behavior And Molecular Simulation

Effective prevention of steel,copper and other metal materials in harsh environment such as acid,seawater solution corrosion is a major strategy related to the national economy and people’s livelihood,so the development of new green,efficient organic corrosion inhibitors is one of the important research directions in the field of chemical engineering and technology.In this paper,the corrosion inhibition mechanism of six new imidazolium and pyridine inhibitors on copper in sulfuric acid solution was deeply discussed through systematic electrochemical testing and surface analysis,and combined with theoretical calculation,the key physical and chemical mechanisms in the metal corrosion inhibition process were elucidated from the atomic and molecular scales,providing theoretical guidance for the development of new organic corrosion inhibitors.The main research work of this paper is as follows:（1）The corrosion inhibition effect of six imidazol and pyridine corrosion inhibitors on copper at 0.5M H₂SO₄ was studied through the corrosion weight loss experiment.The results showed that the corrosion inhibition efficiency increased with the increase of the corrosion inhibitor concentration,and the corrosion inhibition effect of 6-nitroimidazoland[1,2-a]pyridine was the best.Scanning electron microscope was used to observe the surface,which showed that the microstructure of corrosion was consistent with the results of weightlessness experiment.（2）The results of polarization curve showed that the six imidazoland pyridine inhibitors were all mixed corrosion inhibitors.The AC impedance results show that the arc radius of capacitive reactance increases with the increase of corrosion inhibitor concentration,that is,the Rct value of charge transfer resistance in the system increases as well as the Rf value,which improves the corrosion inhibition efficiency.（3）By EDS and XPS experiments,N,Br,C,O,Cl and other elements were detected on the surface of copper,indicating that the corrosion inhibitor was effectively adsorbed on the surface of copper.（4）A series of quantum chemical parameters,including the lowest empty molecular orbital energy and the highest occupied molecular orbital energy,were obtained by density functional theory（DFT）.The stable adsorption configurations of six kinds of molecules on the copper surface were discussed by molecular dynamics simulation,and the results showed that six imidazo-pyridines were closely adsorbed on the Cu（111）surface in parallel state.The corresponding Einh values well verified the experimental results.The results of quantum chemistry calculation and molecular dynamics simulation show that the adsorption effect of 6-nitroimidazo-pyridine[1,2-a]on copper surface is the best.The results of theoretical calculation are in good agreement with the experimental results.