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

Abstract

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.