Department of Chemistry, Aarhus University , Langelandsgade 140, 8000 Aarhus C, Denmark.
Interdisciplinary Nanoscience Center (iNANO), Aarhus University , Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
Langmuir. 2016 Jun 28;32(25):6289-96. doi: 10.1021/acs.langmuir.6b01309. Epub 2016 Jun 14.
Development of versatile methods for graphene functionalization is necessary before use in applications such as composites or as catalyst support. In this study, bipolar electrochemistry is used as a wireless functionalization method to graft 4-bromobenzenediazonium on large (10 × 10 mm(2)) monolayer graphene sheets supported on SiO2. Using this technique, transferred graphene can be electrochemically functionalized without the need of a metal support or the deposition of physical contacts. X-ray photoelectron spectroscopy and Raman spectroscopy are used to map the chemical changes and modifications of graphene across the individual sheets. Interestingly, the defect density is similar between samples, independent of driving potential, whereas the grafting density is increased upon increasing the driving potential. It is observed that the 2D nature of the electrode influences the electrochemistry and stability of the electrode compared to conventional electrografting using a three-electrode setup. On one side, the graphene will be blocked by the attached organic film, but the conductivity is also altered upon functionalization, which makes the graphene electrode different from a normal metal electrode. Furthermore, it is shown that it is possible to simultaneously modify an array of many small graphene electrodes (1 × 1 mm(2)) on SiO2.
在将石墨烯应用于复合材料或催化剂载体等领域之前，有必要开发出多功能的石墨烯功能化方法。本研究采用双极电化学作为一种无线功能化方法，将 4-溴苯重氮盐接枝到 SiO2 支撑的大尺寸（10×10mm²）单层石墨烯片上。使用这种技术，无需金属支撑或物理接触的沉积，就可以对转移的石墨烯进行电化学功能化。X 射线光电子能谱和拉曼光谱用于绘制整个石墨烯片上的化学变化和修饰。有趣的是，无论驱动电势如何，样品之间的缺陷密度相似，而随着驱动电势的增加，接枝密度增加。与使用三电极设置的传统电化学接枝相比，观察到电极的 2D 性质会影响电极的电化学和稳定性。一方面，附着的有机膜会阻止石墨烯，但功能化后导电性也会发生改变，这使得石墨烯电极与普通金属电极不同。此外，还表明可以同时修饰 SiO2 上许多小石墨烯电极（1×1mm²）的阵列。
