Arao Yoshihiko, Kuwahara Riichi, Ohno Kaoru, Tanks Jonathon, Aida Kojiro, Kubouchi Masatoshi, Takeda Shin-Ichi
Tokyo Institute of Technology, School of Materials and Chemical Technology 2-12-1 O-okayama, Meguro-ku Tokyo Japan
Dassault Systèmes ThinkPark Tower 2-1-1 Osaki, Shinagawa-ku Tokyo Japan.
Nanoscale Adv. 2019 Nov 21;1(12):4955-4964. doi: 10.1039/c9na00463g. eCollection 2019 Dec 3.
Developing a mass production method for graphene is essential for practical usage of this remarkable material. Direct exfoliation of graphite in a liquid is a promising approach for production of high quality graphene. However, this technique has three huge obstacles to be solved; limitation of solvent, low yield and low quality (, multilayer graphene with a small size). Here, we found that soluble graphite produced by mechanochemical reaction with salts overcomes the above three drawbacks. Soluble graphite was exfoliated into monolayer graphene with more than 10% yield in five minutes of sonication. The modified graphite was easily exfoliated in a low-boiling point solvent such as acetone, alcohol and water without the aid of a surfactant. Molecular simulation revealed that the salt is adsorbed to the active carbon at the graphite edge. In the case of weak acid salts, the original bonding nature between the alkali ion and the base molecule is retained after the reaction. Thus, alkali metals are easily dissociated in a polar solvent, leading to negative charge of graphene, enabling the exfoliation of graphite in low boiling point solvents. The approach proposed here opens up a new door to practical usage of the attractive 2D material.
开发一种石墨烯的大规模生产方法对于这种卓越材料的实际应用至关重要。在液体中直接剥离石墨是生产高质量石墨烯的一种有前景的方法。然而，该技术有三个巨大的障碍需要解决：溶剂的局限性、低产率和低质量（小尺寸的多层石墨烯）。在此，我们发现通过与盐进行机械化学反应制备的可溶性石墨克服了上述三个缺点。在超声处理五分钟后，可溶性石墨以超过10%的产率剥离成单层石墨烯。改性石墨在丙酮、酒精和水等低沸点溶剂中无需表面活性剂的帮助就能轻松剥离。分子模拟表明盐吸附在石墨边缘的活性炭上。对于弱酸盐，反应后碱离子与碱分子之间的原始键合性质得以保留。因此，碱金属在极性溶剂中容易解离，导致石墨烯带负电荷，从而使石墨能够在低沸点溶剂中剥离。这里提出的方法为这种有吸引力的二维材料的实际应用打开了一扇新的大门。
