Abstract Amino acids are important compounds for GO functionalization because they can improve GO properties for many applications ranging from biomedicine to depollution. However, amino acids can act as nucleophiles or as reducing agents for GO functionalization or reduction, respectively. Hence, we systematically studied the GO functionalization/reduction using glycine as a model amino acid under basic conditions at room temperature. Attenuated total reflectance–Fourier transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy, and Raman spectroscopy were used to characterize the modified GO with glycine. We found that low glycine concentrations produced an epoxide ring opening reaction, whereas an increase in glycine concentration led to GO reduction. The basic medium allowed to conserve the carboxylic acid groups, whereas the GO reduction mechanism was governed by the partial hydrolysis of epoxide groups and the subsequent reduction of carboxylic acids to carbonyls. This article opens up the opportunity to study and control the conditions in which different amino acids could be used for either GO functionalization or GO reduction.

中文翻译：

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在碱性介质下调节甘氨酸对氧化石墨烯的亲核攻击和还原作用

摘要 氨基酸是 GO 功能化的重要化合物，因为它们可以改善从生物医学到净化等许多应用的 GO 特性。然而，氨基酸可以分别作为亲核试剂或还原剂用于 GO 功能化或还原。因此，我们系统地研究了在室温下碱性条件下使用甘氨酸作为模型氨基酸的 GO 功能化/还原。衰减全反射-傅立叶变换红外光谱（ATR-FTIR）、X射线光电子能谱和拉曼光谱被用来表征用甘氨酸修饰的GO。我们发现低甘氨酸浓度会产生环氧化物开环反应，而甘氨酸浓度的增加导致 GO 还原。允许保留羧酸基团的碱性培养基，而 GO 还原机制受环氧基团的部分水解和随后羧酸还原为羰基的控制。本文为研究和控制不同氨基酸可用于 GO 功能化或 GO 还原的条件开辟了机会。