Preparation, Characterization And Properties Of New Porous Carbon Materials

Porous carbon materials have attracted increasing interests, because of their large surface area, light weight, electrical conductivity and chemical stability. The excellent physical and chemical performances make them applicable in the fields of absorbents, catalyst carrier, electrode, energy storage, biomaterials and so on. In this work, we reported an effective and facile method to prepare monodisperse polymer nanoparticles by sol-gel template method, carbon nanoparticles are achieved by carbonization of polymer nanoparticles at a high temperature under an argon atmosphere. The morphology and pore structure of carbon nanoparticles can be controlled by changing the synthetic condition and selecting suitable templates. In the synthesis, Commercial opaque polymer (OP) hollow spheres were used as templates and microreactors for polymerization of resorcinol and formaldehyde monomers. The deionized water and ethanol are used as solvent and dispersant. Resorcinol-formaldehyde was applied as the carbon source. SAXS is used in the characterization of the microstructure of pore systems in the carbon nanoparticles. We study the influence of synthetic condition on pore structure and morphology by SAXS results, such as carbon source concentration, dispersant, post-treatment, CO2 activation condition and so on.When the carbon source concentration is 2N, the solvent and dispersant are the deionized water, synthesis pH is approximate 8, the achieved carbon nanoparticles by carbonization and activation of polymer nanoparticles at a high temperature are monodispersed spherical structure. The graphitization of the porous carbon nanospheres is lower, and carbon nanospheres consist of abundant smaller graphite crystallite. The surface composition of porous carbon nanospheres is C and O. The porous carbon nanospheres have a hierarchical porous structure, which owns micropores, mesopores and macropores. The pore structure of carbon spheres can be improved through CO2 activation, which leads to more micropores and higher surface area. Hierarchical porous carbon spheres exhibit a good electrochemical performance, including the high specific capacitance, high reversibility and excellent electrochemical stability.When the carbon source concentration is 2N, the solvent and dispersant are the mixture of deionized water and ethanol (W/E=1:1), polymer nanoparticles are treated by alkali or acid (pH>10 or pH<6), we can achieve monodispersed carbon bowl-like nanoparticles. The bowl-like carbon particles with typical properties of carbon materials, in particular, have unusual structures, resulting in similar surface area at reduced volume compared with the hollow carbon spheres. Because of their unique bowl-like and hierarchical porous structur, the carbon nanobowls exhibit a good electrochemical performance, especially in high-rate operations.