Synthesize C@SiO2 with independent spaces produced from carbon slices by the confinement of the silica shell for toluene adsorption

Porous carbons with controlled pore structure have attracted great interest owing to their excellent application potential. Herein, we report a simple synthetic route to synthesize the core-shell C@SiO2 spheres with various pore structures by calcining core-shell structured RF@SiO2 (RF = resorcinol-formaldehyde resin). The obtained C@SiO2 spheres had high surface areas (238.5–732.5 m2/g), large pore volume (0.111–0.647 cm3/g) and abundant micro-mesoporous structure. The mesopore size of C@SiO2 spheres can be easily turned in the range of 8–15 nm, by simply modifying the carbonization temperature, size and heating rate of RF@SiO2 spheres. Among these, S–C@SiO2-400 spheres had higher mesopore volume of 0.207 cm3/g, this was related to internal carbon slices structure. Meantime, the toluene adsorption capacity of S–C@SiO2-400 spheres could reach 448.2 mg/g, which increased by 88.73% compared to ordinary carbon spheres. Moreover, the formation mechanism of the mesopore carbon slices structure was evaluated based on controlled experiments. This work provides a new synthetic method of micro-mesoporous carbon spheres, which can further enrich the application of carbon materials.