Well‐defined, stoichiometric derivatives of graphene afford many opportunities in fine‐tuning of graphene properties and hence, extend the application potential of this material. Here, we present the electrochemical properties of cyanographene (G−CN), and graphene acid (G−COOH) in order to understand the role of the covalently attached functional groups on the graphene sheet in electrochemical sensing for the detection of biomarkers. G−CN shows better performance for the negatively charged analytes ascorbic and uric acids when compared to G−COOH. The less‐favourable performance of G−COOH is explained by repulsion between negatively charged analytes and negatively charged functional groups of G−COOH. The capacitance of both materials is in a comparable range, but chronopotentiometry reveals that G−CN shows a greater capacitance than G−COOH. The identified differences in electrochemical properties imprinted by the functional group show that its chemical nature can be exploited in fine‐tuning of the selectivity of electrochemical sensing and energy storage applications.

中文翻译：

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氰基石墨烯和石墨烯酸：石墨烯衍生物的官能团决定了其在电化学传感和电容器中的应用

定义明确的化学计量的石墨烯衍生物为微调石墨烯的性质提供了许多机会，因此扩展了该材料的应用潜力。在这里，我们介绍了氰基石墨烯（G-CN）和石墨烯酸（G-COOH）的电化学性质，以了解在石墨烯片上共价连接的官能团在电化学传感中检测生物标志物的作用。与G-COOH相比，G-CN对带负电的分析物抗坏血酸和尿酸表现出更好的性能。G-COOH的不利性能可以通过带负电荷的分析物与带负电荷的G-COOH官能团之间的排斥来解释。两种材料的电容都在可比较的范围内，但计时电位分析表明，G-CN的电容大于G-COOH的电容。