Eletrochemiluminescence, Quantum Chemical Calculation, Electrochemical Impedance Spectroscopy, Electrochemical Potentiodynamic Polarization Study on the Corrosion Inhibition and Mechanism of Organic Inhibitors for Q235 Carbon Steel in 3.5% NaCl

Xuehui Pang^*, Chunhuan Li, Xiaojian Li, Baocun Zhu, Jian Gao, Qin Wei & Bin Du

Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China

Xuehui Pang, Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China.

Keywords: Corrosion Inhibition; Electrochemiluminescence; Quantum Chemical Calculation; Eis; Potentiodynamic Polarization

Abstract

In this work, two kinds of corrosion inhibitor, 3’,6’-dihydroxy-3H-spiro [isobenzofuran-1,9’- xanthen]-3-one DS and 8-Oxo-8H-acenaphtho [1, 2-b] pyrrole-9-carbonitrile AC, for Q235 carbon steel were studied by eletrochemiluminescence (ECL), quantum chemical calculation by Gaussian03W, electrochemical impedance spectroscopy (EIS), electrochemical potentiodynamic polarization test in 3.5% NaCl. ECL data both showed that the inhibitors emitted weaker luminescence on the carbon steel electrode (CSE) than the case on the glassy carbon electrode (GCE), and the emitted luminescence weakened more for DS than that for AC. ECL method was initially applied. The ECL results were illuminated by the quantum calculation data from the aspect of the energy band. The interaction mechanism between the inhibitors and Fe atoms was illustrated by the quantum chemical calculation data. The EIS data showed that the inhibitors hindered more than 99% charger and mass transmission, R^p decreased and C^dl increased. The potentiodynamic polarization data showed that the inhibitors reduced most of the electrode reaction current j^corr and suppressed the anodic reaction more obviously. Thermomechanical analysis showed that the inhibitors behavior fitted well with Langmuir adsorption isotherm and the interaction strength fell in between the physical and chemical interaction.

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