利用三聚氰胺高温下缩聚产生的g-C3N4作为二维模板,同时利用其与对苯二甲醛发生席夫碱反应产生聚合物以及聚合物的碳化,制备了具有二维形貌的类石墨烯片层碳材料(GLCS),随后,将GLCS用KOH进行活化,得到了具有多孔结构的a-GLCS.对材料进行透射电镜(TEM)、扫描电镜(SEM)、X射线光电子能谱测试(XPS)、拉曼光谱(Raman)和比表面积分析(BET),并将材料用作超级电容器电极材料进行电化学测试.结果表明该方法能够制备得N-维片层碳材料,并且材料中掺杂有一定量的氮元素.GLCS经过KOH活化后,比表面积和电容性能都有了大幅提高,电流密度为1A/g时GLCS和a-GLCS比容量分别为160和300F/g.
As a new kind of carbon material, graphene has unique two-dimensional (2D) structure and outstanding physico- chemical properties, such as high electrical conductivity and large surface area (2675 m^2/g). In recent years, gmphene has exhibited great potential for application as electrode materials in supercapacitors. In this work, a layered graphic carbon ni- tride (g-CaN4) which was generated through polycondensation of melamine was employed as a 2D self-sacrificing template. Then, a nitrogen-doped graphene-like 2D carbon sheets (GLCS) was prepared by the calcination of melamine and tereph- thalaldehyde. This graphene synthesis method is a more facile and cost-effective route comparing with traditional synthetic methods, such as chemical exfoliation of graphite and chemical vapor deposition (CVD). In a typical synthesis, melamine was used as precursor of template and reactant of Schiff-base reaction. The g-C3N4 template was used to confine the as-formed polymer to the interlayer gaps at about 600 ℃. Then, as the temperature continued to rise, the g-C3N4 template undergoes complete thermolysis and the polymer between interlayer gaps was carbonized to be GLCS. Then, after activated by KOH, a porous a-GLCS with high specific surface area and pore volume was obtained. GLCS and a-GLCS were charac- terized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface area measurement, Raman spectroscopy etc. TEM and SEM results showed that GLCS showed well-defined two-dimensional structure, XPS analysis determined the nitrogen-containing functional groups present on the surface of the sample, BET surface area measurement showed that after activated by KOH, the surface area have been obviously improved from 262.8 m^2/g to 478.5 m^2/g. The electrochemical measurement showed that, at the current density of 1 A/g, the specific capacitance of GLCS and a-GLCS are 150 and 300 F/g respectively. W