Abstract Adsorbed amino acids can modulate the behavior of metal nanoparticles in advanced applications. Using a combination of electrochemical experiments, FTIR spectroscopy, and DFT calculations, glutamate species interacting with the Au(111) surface in solution are here investigated. Electrochemical results indicate that the adsorption behavior depends on the solution pH (which controls the glutamate ionization) and on the charge of the surface. Glutamate adsorption starts at potentials slightly negative to the potential of zero charge. The thermodynamic analysis of these results indicates that two electrons are exchanged per molecule, implying that both carboxylic groups become deprotonated upon adsorption. The FTIR spectra reveal that carboxylate groups are bonded to the surface in a bidentate configuration (with both oxygen atoms attached to the surface). Plausible adsorbed configurations, consistent with the whole of these insights, were found using DFT. Moreover, it was observed that glutamate oxidation only takes place when the surface is oxidized, which suggests that this oxidation process involves the transfer of an oxygen group to the molecule, though, according to the FTIR spectra, the main chain remains intact.

中文翻译：

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不同pH值下Au(111)表面的谷氨酸吸附

摘要 吸附的氨基酸可以调节金属纳米粒子在高级应用中的行为。结合电化学实验、FTIR 光谱和 DFT 计算，这里研究了与溶液中 Au(111) 表面相互作用的谷氨酸物质。电化学结果表明吸附行为取决于溶液 pH 值（控制谷氨酸离子化）和表面电荷。谷氨酸盐吸附开始于零电荷电位的略微负电位。这些结果的热力学分析表明每个分子交换了两个电子，这意味着两个羧基在吸附时都去质子化。FTIR 光谱显示羧酸盐基团以双齿构型键合到表面（两个氧原子都连接到表面）。使用 DFT 发现了与所有这些见解一致的合理吸附配置。此外，观察到谷氨酸氧化仅在表面被氧化时发生，这表明该氧化过程涉及氧基团向分子的转移，但根据 FTIR 光谱，主链保持完整。