Abstract The corrosion inhibition and adsorption behavior of glutamic acid (Glu), glutamine (Gln), and their cerium complexes: cerium glutamate (Ce(Glu)) and cerium glutamine (Ce(Gln)) on mild steel in 0.5 M HCl solutions were studied at 25 and 55 °C and concentration range of 25–200 ppm using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopic (EIS) techniques. The inhibition efficiency was found to be dependent on the concentration and temperature of the system. The potentiodynamic polarization results suggest that the compounds act as mixed-type inhibitors with dominant cathodic inhibition. The mechanism of adsorption deduced from the variation of inhibition efficiency with temperature, as well as the activation parameters, suggest significant physisorption of the inhibitor molecules on the metal surface. The experimental data adhere to the Langmuir and El-Awady et al. kinetic adsorption models. The extent of inhibition was found to be Ce-Gln > Gln and Ce-Glu > Glu. The scanning electron microscope was employed for the morphological studies and the characteristic of the protective layer on the steel surface verified using UV-Vis spectroscopy and FTIR spectroscopy. Adsorption of the inhibitors on Fe (110) surface was evaluated theoretically.

中文翻译：

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铈-氨基酸复合物在酸性介质中对低碳钢的缓蚀和吸附性能：实验和 DFT 研究

摘要 研究了谷氨酸 (Glu)、谷氨酰胺 (Gln) 及其铈配合物谷氨酸铈 (Ce(Glu)) 和谷氨酰胺铈 (Ce(Gln)) 在 0.5 M HCl 溶液中对低碳钢的缓蚀和吸附行为。使用动电位极化 (PDP) 和电化学阻抗光谱 (EIS) 技术在 25 和 55 °C 和 25–200 ppm 的浓度范围内进行研究。发现抑制效率取决于系统的浓度和温度。动电位极化结果表明，这些化合物作为混合型抑制剂，具有显着的阴极抑制作用。从抑制效率随温度的变化以及活化参数推导出的吸附机制表明金属表面上的抑制剂分子有显着的物理吸附。实验数据符合 Langmuir 和 El-Awady 等人的观点。动力学吸附模型。发现抑制程度为 Ce-Gln > Gln 和 Ce-Glu > Glu。使用扫描电子显微镜进行形态研究，并使用 UV-Vis 光谱和 FTIR 光谱验证钢表面保护层的特性。理论上评估了抑制剂在 Fe (110) 表面上的吸附。