Graphene has shown great potential as electrochemical electrodes in energy storage and sensor applications due to its unique combination of semiconducting and metallic properties. We here demonstrate that graphene’s semimetallic nature imparts it with a continuously tunable electrochemical reactivity. Extrinsic doping was shown to modify the reaction rate of graphene microelectrode arrays and a direct correlation between graphene’s linearly varying density of states and its electron transfer rate was established. Dynamic control of the charge transfer process enabled the variation of graphene’s reaction rate over 1 order of magnitude and was confirmed by a simple Gerischer–Marcus charge transfer kinetics model. The observed fine control over graphene’s electrochemical properties enabled a 2-fold increase in the resolution of an electrochemical impedance sensor. These results not only explain previous observations of graphene’s spatially varying electrochemical reactivity and highlight the importance of doping control in graphene-based electrochemical applications but also open up exciting routes for combining electronics and electrochemistry in novel sensors and actuators.

中文翻译：

---

石墨烯电化学反应的静电控制

石墨烯由于具有半导体和金属特性的独特组合，在储能和传感器应用中已显示出作为电化学电极的巨大潜力。我们在这里证明石墨烯的半金属性质赋予其连续可调的电化学反应性。研究表明，外部掺杂改变了石墨烯微电极阵列的反应速率，并且建立了石墨烯线性变化的态密度与其电子传输速率之间的直接相关性。动态控制电荷转移过程可以使石墨烯的反应速率发生1个数量级的变化，并通过简单的Gerischer-Marcus电荷转移动力学模型得到证实。观察到的对石墨烯电化学性能的精细控制使电化学阻抗传感器的分辨率提高了2倍。这些结果不仅解释了石墨烯在空间上变化的电化学反应性的先前观察结果，并突出了掺杂控制在基于石墨烯的电化学应用中的重要性，而且开辟了将电子学和电化学技术结合到新型传感器和致动器中的令人兴奋的途径。