Large scale synthesis of nitrogen-doped nanoporous carbon spheres based on miniemulsion polymerization for efficient dye removal

Abstract

Functional nanoporous carbon spheres (NPCS) are important for applications ranging from adsorption, catalysis, separation to energy storage and biomedicine. We demonstrated a facile method to synthesize uniform NPCS, involving the formation of polyacrylonitrile@poly (γ-methacryloxypropyl trimethoxysilane) (PAN@PMPS) composite particles via seeded miniemulsion polymerization of PAN nanoparticles (NPs), carbonization, and subsequent removal of the outer PMPS shell. The influences of the addition of water phase inhibitor sodium nitrite and crosslinking agent divinylbenzene on the morphologies of PAN@PMPS composite particles were investigated. The adsorption performance of NPCS towards methylene blue (MB) was investigated. The results showed that uniform PAN@PMPS composite particles were obtained with average diameters of ~ 149 nm when using NaNO2 as water phase inhibitor. PMPS layer prevented PAN core aggregation/fusion during the carbonization process, resulting in the formation of individual NPCS. Uniform NPCS exhibiting diameters of ~ 122 nm, with the accessible surface area (~ 202 m2/g), and high nitrogen content (13.75 wt%) was obtained. NPCS exhibited excellent adsorption capacity towards MB with the maximum value of 117.89 mg/g at 298 K from aqueous solution. This miniemulsion polymerization-based strategy provides a new, facile approach to prepare high-performance porous carbon spheres in industrialization promise.