Abstract Cysteine amino acid is well known as an effective green corrosion inhibitor. Due to the structural similarity between d -penicillamine (PA) drug and cysteine, it is expected PA also acts as a green corrosion inhibitor. Herein we describe the corrosion inhibition ability of PA and l -cysteine (Cys) on the mild steel in 1 M HCl using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). Experiments were performed in various concentrations of Cys and PA and different immersion times. The results suggested that both Cys and PA can be used as effective corrosion inhibitors. PA and Cys are mixed-type inhibitors; however, PA affected significantly only the cathodic reaction. The adsorption of inhibitors followed the Langmuir adsorption isotherm. Electronic structure of Cys and PA was elucidated with density functional theory (DFT) calculations. Molecular adsorption on Fe(110) was investigated using molecular dynamics (MD) simulations.

中文翻译：

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青霉胺药物和半胱氨酸作为低碳钢水溶性绿色缓蚀剂的实验和计算研究

摘要 半胱氨酸是众所周知的有效绿色缓蚀剂。由于 d-青霉胺 (PA) 药物和半胱氨酸之间的结构相似，预计 PA 也可作为绿色腐蚀抑制剂。在此，我们使用动电位极化、电化学阻抗谱 (EIS) 和扫描电子显微镜 (SEM) 描述了 PA 和 l-半胱氨酸 (Cys) 在 1 M HCl 中对低碳钢的腐蚀抑制能力。实验在不同浓度的 Cys 和 PA 以及不同的浸泡时间下进行。结果表明，Cys 和 PA 均可作为有效的缓蚀剂。PA和Cys是混合型抑制剂；然而，PA 仅显着影响阴极反应。抑制剂的吸附遵循朗缪尔吸附等温线。Cys 和 PA 的电子结构通过密度泛函理论 (DFT) 计算阐明。使用分子动力学 (MD) 模拟研究了 Fe(110) 上的分子吸附。