Synthesize of large-sized porous carbon spheres with controllable N-content via spray-drying and photo-induced RAFT polymerization

A method combined spray-drying process with light-induced reversible addition fragmentation chain transfer (RAFT) polymerization was used to synthesize N-doped carbon spheres (N-CS). Firstly, the common used carbon precursor phenolic resin which called Resol was modified with a chain transfer agent (CTA). Then, the mixed ethanol solution of CTA modified Resol, F127, TEOS, and HCl was used as starting material. After a typical spray-drying process, uniformed and discrete composite spheres in regular size (70 μm) were obtained. The RAFT polymerization of acrylonitrile was initiated under the irradiation of blue LED at the surface of spheres. Through such manner, controlled amount of polyacrylonitrile was introduced onto the surface of carbon sphere. After calcination at 900 °C and etching, the obtained porous N-CS (60 μm) showed controllable total N content up to 10.8 wt%, tunable high surface area up to 1130 m2/g and good CO2 absorptivity which can up to 4.34 mmol/g at 273 K and 4.13 mmol/g at 298 K at 1.0 bar.