由石墨炔及其衍生物高温高压合成多孔三维碳材料

The three dimensional (3D) carbon networks with graphene-like segments interconnected by sp3 bonds show high electrical conductivity, excellent mechanical properties, low density and large surface area. Many 3D carbon networks with different pore sizes and edge structures were predicted theoretically, but only very few of them were synthesized. The precursors were usually graphene and nanotubes constructed by sp2 carbon, and the products usually have disordered structure with properties far below the theoretical results. Recently, theoretical calculation predicted that graphyne can transform to well-defined 3D carbon networks under high pressure, through the interlayered cross-linking of the carbyne groups (sp carbon). In this proposal, we focus on the synthesis of the 3D carbon networks from graphyne under high pressure and high temperature (0-60GPa and room temperature - above 1000K), and investigate their properties including the electrical conductivity, mechanical properties and absorption performance. By exploring the in situ spectroscopy, diffraction, the ex situ chemical and material analysis methods as well as the theoretical calculation, we will uncover the phase transition and reaction process of the graphyne under extreme conditions. In addition, we will also try to tune the structure and the properties of the 3D carbon networks by modifying the stacking and chemical compositions of the graphyne. By combining the chemical synthesis, the extreme conditions and multiple cutting-edge analysis methods, the relationship between the structure of graphyne, thermodynamics conditions (pressure and temperature) as well as the structures and properties of the products will be investigated in this proposal, which will provide important references for tuning the 3D carbon networks in the atomic scale.

由石墨烯片层构筑的三维多孔碳具有优异的力学、电学性能以及低的密度与高的比表面积。人们预测了大量的具有不同孔洞及边带结构的三维多孔碳，但是合成方面只有以石墨烯、碳纳米管为前体的少量工作。最近，有理论预测石墨炔中活泼的sp碳在高压下会发生层间聚合，形成这类三维多孔碳。本项目主要以石墨炔为前体，运用极端条件（0-60GPa, 300K-1000K以上）探索合成三维多孔碳，并研究其电学、力学及吸附性质。同时利用原位的光谱、衍射手段、离位的化学、材料分析手段和理论计算探究石墨炔的相变规律与基本反应类型。进一步通过调控石墨炔的堆积方式、化学组成来调控产物的结构和性质。本项目将极端条件、化学合成与多种前沿表征手段相结合，系统研究石墨炔的结构、堆积方式、温度、压力与产物结构、性质间的关系，为在分子水平上实现对三维碳结构和性质的调控开辟一条新路。

三维多孔碳材料由于具有优异的力学、电学性能以及低的密度与高的比表面积而引起了大家的广泛兴趣。理论预测了大量的具有不同结构的三维多孔碳，但是合成上却进展缓慢。最近的理论预测显示石墨炔中的活泼sp碳可以在高压下发生层间聚合，形成三维多孔碳材料。本项目系统研究了石墨炔、石墨炔衍生物及其组成单元在高压常温、高压高温条件下的相变、化学反应过程以及导电性质。研究结果显示石墨炔及其衍生物在高压常温下可以实现层间交联，炔的sp碳转化为sp2碳，同时伴随导电性的增加。在高温高压下，石墨炔可以转变为全sp3碳的晶态碳材料且产物的结构与反应的温度压力条件密切相关。进一步通过对石墨炔的基本组成单元芳环、炔以及芳基炔化合物的研究显示芳环的聚合压力较高（20 GPa），炔基的聚合压力较低（4 GPa），而在苯基炔体系中常常发生苯与炔基的协同环化反应，使得芳环的反应压力大大降低。在反应类型方面，我们发现了一系列高压下特有的协同反应，如芳环体系中的[1,3,5]周笼反应以及苯环与炔参与的[4+2]Diels-Alder反应并初步指明了反应的类型与反应物分子结构和晶体结构的关系。本项目综合利用原位的光谱、衍射手段、离位的化学、材料分析手段和理论计算探究了石墨炔的相变和基本反应规律，系统研究了石墨炔的基本组成单元的反应类型、调控规律以及静水压条件、石墨炔的取代基团、温度、压力与产物结构、性质的关系，为认识石墨炔在高压下的化学反应过程、实现三维碳结构的合成奠定了理论基础。