Nowadays, the increasingly serious electromagnetic wave (EMW) pollution and electromagnetic interference (EMI) problems urgently require the development of high-performance electromagnetic attenuation (EMA) materials with tunable green low-reflective EMI shielding and efficient EMW absorption properties. Herein, the pepper wood-like Co3Fe7@C nanotubes were constructed by a combined strategy of metal chelates derivatization, self-polymerization, and in-situ carbon reduction, composed of magnetic alloys Co3Fe7 nanoparticles (size of 7.5 nm) densely embedded in carbon nanotubes. The EMW absorption and EMI shielding capabilities of the samples with different filling ratios were investigated. Benefiting from the synergistic attenuation mechanism provided by the hollow tubular structure and strong magnetic/dielectric components, the Co3Fe7@C nanotubes with protrusions on the surface displayed superior EMW absorption performances at extremely low filling ratio (5 wt%) with a
minimum reflection loss (RLmin) of -107.4 dB and an effective absorption bandwidth (EAB) of 11.6 GHz. Notably, the EMI shielding effectiveness of the optimized sample reaches up to 44.94 dB, while the effective absorption efficiency of the samples with filler loading over 15 wt% are all over 90 %. Furthermore, the composite with a coating thickness of 2.0 mm also exhibits an ideal radar cross-sectional (RCS) reduction of 21.2 dBm2 at 0°. This study provides unique insights into the design and synthesis of high-efficiency EMA materials, and the Co3Fe7@C nanotubes are expected to be practically applicable in complex environments.