We report a facile approach to directly chlorinate graphene from an aqueous sodium chloride solution under ambient conditions. By applying a moderate anodic voltage to substrate-supported monolayer graphene, the resultant chlorine radicals generated at the graphene surface enable efficient chlorination: X-ray photoelectron spectrum confirms the formation of C–Cl bonds, and reaction voltage-tunable Cl:C atomic ratios of up to 17% are achieved. In comparison, we find the corresponding electrochemical graphene bromination and iodination reactions much less viable. Electrical and Raman characterizations show substantial p-doping for the chlorinated graphene, yet good basal-plane integrity and electrical properties are maintained. Interference reflection microscopy and pH-dependent experiments next help elucidate the competition between the radical-mediated electrochemical chlorination and oxidation in the process, and rationalize acidic conditions for optimal chlorination. Reaction in a mixed NaCl–NaN₃ solution shows the electrochemical chlorination to be fully suppressed by azidation, yet a sequential, two-step chlorination-azidation approach permits facile bifunctionalization.

中文翻译：

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从NaCl水溶液中进行石墨烯的简便，电化学氯化

我们报告了一种在环境条件下从氯化钠水溶液直接氯化石墨烯的简便方法。通过向衬底支撑的单层石墨烯施加适度的阳极电压，在石墨烯表面产生的氯自由基可实现有效的氯化作用：X射线光电子能谱证实了C–Cl键的形成以及反应电压可调的Cl：C原子比达到了17％。相比之下，我们发现相应的电化学石墨烯溴化和碘化反应不太可行。电气和拉曼表征出现实质性p-掺杂氯化石墨烯，但仍保持了良好的基面完整性和电性能。干扰反射显微镜和pH依赖性实验接下来可帮助阐明自由基介导的电化学氯化和氧化过程之间的竞争，并使酸性条件合理化以实现最佳氯化效果。在混合的NaCl–NaN ₃溶液中的反应表明，叠氮化可完全抑制电化学氯化，但是连续的两步氯化叠氮化方法可实现简便的双官能化。