Kinetics-mediated assembly assisted precise synthesis of magnetic ordered mesoporous carbon nanospheres for ultra-efficient electromagnetic wave absorption

Magnetic ordered mesoporous carbon nanospheres (OMCNs) show tremendous potential in the electromagnetic wave absorption (EMWA) field, yet their precise fabrication with a tunable pore architecture and highly dispersed magnetic components still remains a considerable challenge. Herein, we propose a kinetics-mediated assembly assisted synthesis strategy to achieve two types of high-quality magnetic OMCNs with dendritic-like mesopores (Ni/OMCN-D) and spherical mesopores (Ni/OMCN-S). These two nanospheres possess a high surface area (∼400 m² g⁻¹), large pore volume (∼0.45 cm³ g⁻¹), plentiful mesopores (∼10 nm), and uniform and highly dispersed Ni nanoparticles, which endow them with superior EMWA performance. Ni/OMCN-D delivers a maximum refection loss (RL_max) of −72.2 dB at only 2.0 mm and its effective absorption bandwidth (EAB) from 7.8 to 12.1 GHz covers the whole X band at 2.75 mm. Ni/OMCN-S has a RL_max of up to −47.1 dB with just 1.9 mm thickness and its EAB (11.8-18.0 GHz) entirely covers the Ku band at 2.1 mm. The mechanisms for the excellent EMWA performance are expounded based on the unique mesoporous structure as well as the dielectric-magnetic synergy. This proposed strategy offers valuable insights toward exploring novel function-integrated nanostructures for multiple applications.