介孔及碳纳米材料讲义.ppt

金刚石的性能 高熔点：due to strong directional covalent bonds (3550 ?C) 硬度高：because it is difficult to break atoms apart or move them in relation to one another 不导电：because electrons are localized in specific bonds 不溶于有机或无机的溶剂：because molecular bonds are stronger than any intermolecular forces 石墨 碳原子以sp2 方式杂化 碳原子形成六圆环并且垂直于六圆环平面有p-电子轨道. p-电子轨道使得石墨片层间存在范德华力 石墨的性质 与金刚石不同的是 具有导电性 片层间可以相互移动，因而可以被用作润滑剂 与金刚石相同的是 高熔点(higher actually because of delocalized e-, 3653?C) 不溶 (same reason) 石墨烯 二维的原子厚度的片层，由三维的石墨剥离得到，是可以翘曲成零维的富勒烯、卷曲成一维的碳纳米管，堆垛成三维的石墨 Fullerenes Carbon nanotube Graphite 碳的六圆环组成的二维片层 碳原子间以Sp2 杂化方式连接 是富勒烯、碳纳米管和石墨的基本构成单元 石墨烯的结构 In graphene, carbon atoms (green dots) are bonded together through sp2 hybridization (orange lines). -Graphene and graphite are great conductors along the planes. Electrons in p-orbitals above and below plane p-orbitals become conjugated across the plane Electrons free to move across plane in delocalized orbitals Extremely high tensile strength 性能 很高的杨氏模量 (~1100 GPa), 很高的断裂强度 (~125 GPa), 导热性好 (~5000W m-1K-1), 电子迁移速度快 (200 000 cm2 V-1 s-1), 高的表面能 (calculated value, 2630 m2 g-1), 很好的化学稳定性和光学透过率 量子霍尔效应和量子隧穿效应 从上而下的制备方法 (Top-Down) 从下而上的制备方法 (Bottom-Up) 石墨烯的制备方法 从下而上的制备方法 (Bottom-Up) Schematic illustrations of routes to graphene and related conjugated carbon monolayer membrane materials. a) Reduced graphene oxide (GO) flakes by chemical exfoliation from graphite powder. b) Graphene nanoribbons (GNRs) from carbon nanotubes. c) Graphene from CVD growth on metal films (e.g. Ni). d) Graphene from epitaxial growth on SiC by Si sublimation. e) Conjugated carbon monolayer membranes from chemical crosslinking of self-assembled monolayers (SAMs). 从下而上的制备方法的优缺点比较 从上而下的制备方法 (Top-Down) AFM image of reduced graphene oxide flakes 从上而下的各种制备方法之优缺点比较 碳纳米管 碳纳米管可以看成是卷曲的石墨烯 Schematic of a CNT STM image of CNT SWCNT capped with half of a C60 fullerene molecule 单壁碳纳米管 直径为1-6 nm 多壁碳纳米管 直径nm → μm * 碳纳米管的合成 碳纳米管主要有三种合成方式： 电弧放电法 Laser abl