Pressure enabled organic reactions via confinement between graphene layers

Hyeon Suk Shin

Department of Chemistry & Low-Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea

Chemical reactions conducted at high pressures provide opportunities for realising new synthesis chemistries and achieving novel states of matter. Many industrial chemical reactors operate at pressures of few thousand atmospheres but facile application of very high pressures (>1 GPa), where interesting reactions can occur and new materials can be realized, is challenging. Confinement of reactants within nanoscale spaces of low dimensional materials (pores such as zeolites and metal organic frameworks and carbon nanotubes) has been shown to provide non-equilibrium conditions for synthesis of novel molecules³ and tuning of chemical reactivity. While few studies have reported chemistry within zero dimensional pores and one dimensional nanotubes, organic reactions in confined spaces between 2D materials have yet to be explored. Here we demonstrate that reactants confined between atomically thin sheets of graphene or hexagonal boron nitride experience pressures as high as 7 GPa, which allows the propagation of solvent-free organic reactions that ordinarily do not occur under standard conditions. Specifically, we show that cyclodehydrogenation of hexaphenylbenzene without catalysts as a proof of concept and oxidative polymerisation of dopamine into sheet-like crystalline structure are enabled by the effective high pressure experienced by the reactants between the graphene layers. The graphene/polydopamine/graphene reaction results in a novel composite material that possesses higher Young’s modulus (430 GPa) than pure graphene layers (300 GPa) and an exceptionally low water vapor transmission rate of < 0.1 g-m^-2-day^-1 – nearly an order of magnitude lower than the state-of-the-art water-diffusion barriers for graphene and hBN. Our results demonstrate a facile, general approach for performing new high-pressure chemistry based on confinement of reactants within graphene layers that provides opportunities for realizing new materials with extraordinary properties.

* 졸업논문 교과목 수강자 세미나 필수 참석 안내
석사, 석박통합, 박사과정이 수강하는 <졸업논문연구학점 1~6>수강자는 학과에서 개최하는 목요일 정규세미나에 반드시 참석해야함.

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