Synthesis of Core-Shell Structured Porous Nitrogen-Doped Carbon@Silica Material via a Sol-Gel Method

Core shell structured nitrogen-doped porous carbon@silica material with uniform structure and morphology was synthesized via a sol-gel method. During this process, a commercial triblock copolymer and the in situ formed pyrroleformaldehyde polymer acted as cotemplates, while tetraethyl orthosilicate acted as silica precursor. The synergetic effect of the triblock copolymer and the pyrrole-formaldehyde polymer enables the formation of the core-shell structure. Herein, the pyrroleformaldehyde polymer acted as not only the template, but also the nitrogen-doped carbon precursor of the core. The obtained core shell structured porous material possesses moderate Brunauer Emmett Teller specific surface area (410 m(2) g(-1)) and pore volume (0.53 cm(3) g(-1)). Moreover, corresponding hollow silica spheres or nitrogen-doped porous carbon spheres can be synthesized by calcining the core shell structured material in air or etching it with HF. The X-ray photoelectron spectroscopy results reveal that the nitrogen states of the obtained material are mainly pyridinic-N and pyridonic-N/pyrrolic-N, which are beneficial for carbon dioxide adsorption. The carbon dioxide uptake capacity of the nitrogen-doped carbon spheres can reach 12.3 wt % at 273 K and 1.0 bar, meanwhile, the material shows good gas adsorption selectivities for CO2/CH4 and CO2/N-2.