Abstract Corrosion inhibitors based on environmentally friendly and harmless products are currently being studied and developed. The corrosion inhibition properties of caffeine (1,3,7-trimethylxanthine) on copper corrosion in aqueous chloride solution (3.5 wt.% NaCl) are analysed here using stationary and transient electrochemical methods, and a theoretical study based on density functional theory is carried out. Caffeine is a very competitive compared to the chemical inhibitors that are often used for copper protection. Electrochemical and impedance experiments reveal that the protective efficiency of caffeine reaches a value of 96% at a concentration of 10−2 mol L−1. Based on these results, the Langmuir model appears to be the best representation of the adsorption of caffeine onto the copper surface. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction (XRD) were used to determine the surface morphology and the chemical composition of the copper surface in chloride media, in the absence and presence of caffeine. The results show the development of a mechanism of corrosion inhibition. In order to confirm the correlation between the inhibitory effect and the molecular structure of caffeine, quantum chemical parameters are used to calculate its electronic properties.

中文翻译：

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环境友好型缓蚀剂咖啡因在铜/氯化物溶液界面的表面分析及吸附行为

摘要 目前正在研究开发基于环保无害产品的缓蚀剂。本文采用稳态和瞬态电化学方法分析了咖啡因（1,3,7-三甲基黄嘌呤）对氯化物水溶液（3.5 wt.% NaCl）中铜腐蚀的缓蚀性能，并进行了基于密度泛函理论的理论研究出去。与通常用于铜保护的化学抑制剂相比，咖啡因具有很强的竞争力。电化学和阻抗实验表明，咖啡因的保护效率在 10-2 mol L-1 的浓度下达到 96% 的值。基于这些结果，Langmuir 模型似乎是咖啡因吸附到铜表面的最佳代表。使用扫描电子显微镜结合能量色散 X 射线光谱和 X 射线衍射 (XRD) 来确定在不存在和存在咖啡因的情况下，氯化物介质中铜表面的表面形态和化学成分。结果表明腐蚀抑制机制的发展。为了证实咖啡因的抑制作用与分子结构之间的相关性，利用量子化学参数计算其电子性质。