Enhanced stability and metallic modification of polymeric and carbonaceous nanospheres through Precursor engineering via one-pot aqueous strategy assisted with iron ions
The synthesis of monodisperse mesoporous carbon nanospheres (MCNs) with diameter less than 500 nm from polymeric nanoparticle precursors remains challenging due to the spontaneous aggregation of nanospheres and low thermal stability of polymer. Herein, a one-pot synthesis method was developed to prepare solidified polymer nanospheres under acidic conditions, where Fe3+ ions not only served as mediators to coordinate with the phenolic hydroxyl groups in the linear-condensation polymer chains to form 3D metal-organic framework-like skeleton but also as a precursor of magnetic species. The solidified structures substantially enhanced the thermal stability of polymeric frameworks and effectively mitigated the fusing of polymeric nanospheres, leading to Fe-nanoparticles incorporated MCNs with well-developed mesoporosity. Compared with the soft-template method with hydrothermal curing process, the present method integrates the low-temperature solidification and metal-incorporation processes into one procedure, which afford a convenient and energy-saving route to the synthesis of monodisperse MCNs containing functional nanoparitcles. Diverse morphologies such as bulk, polyhedrons, and spheres could be easily controlled by utilizing the difference of thermal stability of polymeric nanospheres, which is closely related with curing temperature. By optimizing the synthesis parameters, monodisperse MCNs incorporated with ultrafine Fe3O4 nanocrystals can be successfully synthesized. The resultant Fe3O4-incorporated MCNs showed a large specific surface area of 673 m2 g−1, uniform pore diameter of 3.8 nm, and high saturation magnetization strength of 24.6 emu g−1, leading to high adsorption capacity for methyl orange and methylene blue as well as rapid separation of the adsorbent via magnetic attraction. The results in present work provide a paradigm for the preparation of functionalized MCNs through precursor engineering.