School of Physical and Mathematical Science, Division of Chemistry and Biological Chemistry, Nanyang Technological University, 21 Nanyang Link, Singapore.
Nanoscale. 2011 May;3(5):2256-60. doi: 10.1039/c1nr10136f. Epub 2011 Apr 11.
There is enormous interest in the investigation of electron transfer rates at the edges of graphene due to possible energy storage and sensing applications. While electrochemistry at the edges and the basal plane of graphene has been studied in the past, the new frontier is the electrochemistry of folded graphene edges. Here we describe the electrochemistry of folded graphene edges and compare it to that of open graphene edges. The materials were characterized in detail by high-resolution transmission electron microscopy, Raman spectroscopy, high-resolution X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry. We found that the heterogeneous electron transfer rate is significantly lower on folded graphene edges compared to open edge sites for ferro/ferricyanide, and that electrochemical properties of open edges offer lower potential detection of biomarkers than the folded ones. It is apparent, therefore, that for sensing and biosensing applications the folded edges are less active than open edges, which should then be preferred for such applications. As folded edges are the product of thermal treatment of multilayer graphene, such thermal procedures should be avoided when fabricating graphene for electrochemical applications.
由于可能的储能和传感应用，人们对研究石墨烯边缘的电子转移率非常感兴趣。虽然过去已经研究了石墨烯边缘和基面的电化学，但新的前沿是折叠石墨烯边缘的电化学。在这里，我们描述了折叠石墨烯边缘的电化学，并将其与开放石墨烯边缘的电化学进行了比较。通过高分辨率透射电子显微镜、拉曼光谱、高分辨率 X 射线光电子能谱、电化学阻抗谱和循环伏安法对材料进行了详细的表征。我们发现，对于亚铁氰化物/铁氰化物，与开放边缘位点相比，折叠石墨烯边缘的非均相电子转移速率显著降低，并且与折叠边缘相比，开放边缘的电化学性质提供了更低的生物标志物潜在检测。因此，很明显，对于传感和生物传感应用，折叠边缘不如开放边缘活跃，因此应该优先考虑用于此类应用。由于折叠边缘是多层石墨烯热处理的产物，因此在为电化学应用制造石墨烯时应避免这种热处理。
