Preparation and adsorption property of novel inverse-opal hierarchical porous N-doped carbon microspheres

Abstract The design of pore structure is the key factor for the performance of porous carbon spheres. In this work, novel micron-sized colloidal crystal microspheres consisting of fibrous silica (F-SiO2) nanoparticles are firstly prepared by water-evaporation-induced self-assembly of F-SiO2 nanoparticles in the droplets of an inverse emulsion system to be used as sacrificial templates. Acrylonitrile (AN) was infiltrated in the voids of the F-SiO2 colloidal crystal microspheres, and in-situ induced by 60Co γ-ray to polymerize into polyacrylonitrile (PAN). After the PAN-infiltrated F-SiO2 colloidal crystal microspheres were carbonized and etched with HF solution, novel micron-sized inverse-opal N-doped carbon (IO-NC) microspheres consisting of hollow carbon nanoparticles with a hierarchical macro/meso-porous inner surface were obtained. The IO-NC microspheres have a specific surface area as high as 266.4 m2/g and a molar ratio of C/N of 5. They have a good dispersibility in water, and show a high adsorption capacity towards rhodamine B (RhB) up to 137.28 mg/(g microsphere). This work offers a way to obtain novel micron-sized hierarchical macro/meso-porous N-doped carbon microspheres, which opens a new idea to prepare high-performance hierarchical porous carbon materials.