【作者】 吉俊懿；

【导师】 张凤宝；

【作者基本信息】 天津大学 ， 化学工程， 2013， 博士

【摘要】 石墨烯具有独特的二维结构以及优异的物理化学性质，2004年被发现以来迅速成为了纳米领域研究的热点，石墨烯及其衍生物在表面化学改性和化学能量存储方面的研究吸引了越来越多的关注。本研究利用石墨烯片层的化学稳定性，使用自由基加成的方法将对苯磺酸基团通过共价键接载在石墨烯片层表面，并首次作为石墨烯基固体酸催化剂进行水解反应的探索。分析结果显示，磺酸根均匀地分布在石墨烯片层表面，磺酸根浓度达到2.0mmol g–1。在作为固体酸催化水解反应中时，磺酸化石墨烯具有64%的转化率，接近浓硫酸的催化活性。同时，该固体酸具有可重复利用的优点，五次回收复用之后催化活性未发生改变。此外，通过将磺酸化石墨烯上的磺酸根还原为巯基，得到了巯基化石墨烯，利用巯基和贵金属/金属氧化物之间的强相互作用力，首次通过简单混合即可制备得到不同金属/金属氧化物-石墨烯复合材料。以泡沫镍为模板，通过化学气相沉积(CVD)法合成出具有三维结构的泡沫石墨，该新型三维材料具有电导率高、热导率高，质量轻等特点，在能量存储方面具有广阔的应用前景。以泡沫石墨为模板，通过简单滴加涂布的方式将包裹有石墨烯的纳米硅颗粒均匀地负载在泡沫石墨上得到三维复合材料。该复合材料能够直接用于锂离子电池负极，具有983mAh g–1的总质量比容量，是目前商业化石墨锂电池负极(244mAh g–1)的四倍。该方法制备方式简单，可规模化生产，具有替代当前电池负极材料的前景。通过水热反应得到氢氧化镍/泡沫石墨复合材料，氢氧化镍由厚度为20nm左右的纳米片层自主装成多孔薄膜结构。泡沫石墨能够有效提高复合材料的电子传输能力，而氢氧化镍纳米多孔结构能有效降低离子在材料中的传输距离，提高活性材料利用率。将氢氧化镍/泡沫石墨复合材料组装成为非对称超级电容器，体现出与当前先进商业化超级电容器相当的能量密度(6.9Wh kg–1)以及更加优异的功率密度(44.0kW kg–1)。该氢氧化镍/泡沫石墨复合材料制备方式简单，易于大规模生产，有望成为商业化新型超级电容器电极。更多还原

【Abstract】 Graphene, a two dimensional carbon material with high electrical conductivity, superiormechanical flexibility and low density, has aroused an increasing interest in the field ofnanomaterials research. Graphene and its derivants attract immense attentions in the applicationsof heterogeneous catalysis and energy storage.To Utilize the advantages of the excellent chemical stability and large surface area ofgraphene, a strategy of covalently attachment of sulfonic acid-containing aryl radicals ongraphene surface is explored. The–SO3H group is uniformly dispersed on the surface ofsulfonated graphene with a loading density of2.0mmol g–1. When testing the sulfonatedgraphene as a solid acid catalyst, a conversion rate of64%in hydrolysis reaction is achieved.The catalytic activity is comparable with the concentrated sulfuric acid. Meanwhile, the catalystexhibites excellent reuse stability, and the conversion rate remains unchanged after5runs. Onthe other hand, by reducing the–SO3H group to–SH group, sulfhydrylated graphene is obtained.Taken advantage of the strong bonding between–SH group and metal/metal oxide nanoparticles,metal-graphene composite can be easily obtained by simply mixing the pre-prepared metal/metaloxide nanoparticles solution and sulfhydrylated graphene solution.A three-demensional (3D) ultrathin-graphite foam (UGF) can be prepared via chemicalvaper deposition (CVD) method. The ultrathin-graphite foam provides a three-dimensionalinterconnected network with high electrical conductivity, high thermal conductivity and lowweight, which can be used as energy storage material. A Si/graphene composite is drop-casted onan ultrathin-graphite foam, forming a Si electrode with3D network. The Si/graphene/UGFelectrode has a high overall gravimetric capacity of983mAh g–1when acting as a lithium ionbattery anode electrode, which is4times as high as graphite anode commercially used (244mAhg–1). The simple preparation may be industrially scalable, suggesting that the Si/graphene/UGFelectrode is an attractive candidate for replacing the traditional flat electrode of commercial LIBs.Nanoporous nickel hydroxide (Ni(OH)2) thin film is grown on the surface of ultrathin-graphite foam (UGF) via a hydrothermal reaction. The resulting free-standing Ni(OH)2/UGFcomposite is used as the electrode in a supercapacitor without the need of additional binder ormetal-based current collector. The highly conductive3D UGF network facilitates electrontransport and the porous Ni(OH)2thin film structure shortens ion diffusion paths and facilitates the rapid migration of electrolyte ions. An fully packaged asymmetric supercapacitor constitutewith Ni(OH)2/UGF electrode shows a higher (2to27times higher) power density (44.0kW kg–1)and a comparable energy density (6.9Wh kg–1), when comparing with the high-endcommercially available supercapacitors. This simple and cost-effective synthetic method can beapplied to other electroactive materials and offers promise for high power energy storage.更多还原