Fibrous N-doped hierarchical porous carbon microspheres: Synthesis and adsorption performance

The creation of high surface area and effective active sites is the key problem for the synthesis of high-performance porous carbon materials. In this work, polyacrylonitrile-coated fibrous silica (F-SiO2@PAN) microspheres were prepared by in situ polymerization of acrylonitrile on fibrous mesoporous silica microspheres induced by gamma-ray radiation. After F-SiO2@PAN microspheres were carbonized and etched with hydrofluoric acid, uniform fibrous N-doped porous carbon (FNC) microspheres with an average size of 286 nm and a molar ratio of C/N of 5.2 were successfully prepared. As revealed by TEM, SEM, and N-2 adsorption-desorption isotherms analysis, FNC microspheres have a hierarchal micromacroporous structure with a particular high surface area of 554.5 m(2)/g. The FNC microspheres also exhibit a good water dispersibility and an excellent adsorption ability to rhodamine B in water. The equilibrium adsorption capacity of FNC microspheres could reach 95.4 mg/g, which is 1.6 times as that of the primary silica template microspheres. The adsorption kinetics and thermodynamics of FNC microspheres are in accord with the pseudo-second-order kinetic equation and Freundlich isotherm model, respectively. This work provides a facile synthesis method for novel N-doped hierarchical micromacroporous carbon microsphere as a potential high-performance adsorbent material. (C) 2017 Published by Elsevier B.V.