Symbiotic strategy of exogenous carbon and NiCo-MOFs for intelligent switching of low/medium electromagnetic response bands†

Abstract

The intrinsic porous topology and differential charge distribution trends of bimetallic metal–organic framework (MOF)-based electromagnetic wave absorbers enhance their value through the development of non-carbonization processes. The introduction of symbiotic carbon components with varying dimensional structures and graphitization degree contributes to regulating the growth environment and electromagnetic response modes of bimetallic MOFs. In this work, the intelligent regulation of the electromagnetic wave absorption band was achieved by incorporating NiCo-MOF into 1D carbon fibers and 3D alginate-derived carbon networks, with a particular focus on addressing urgent low-frequency electromagnetic pollution. Notably, under appropriate ratios of carbon components and NiCo-MOF, NiCo-MOF@C-α exhibited an RL_min of −41.23 dB at 4.96 GHz with a matching thickness of 3.0 mm, while NiCo-MOF@C-β showed an RL_min of −53.25 dB at 8.72 GHz with a matching thickness of 2.5 mm. The realization of the band-modulation function in high-performance bimetallic MOF-based electromagnetic wave absorbers was attributed to the balance and optimization of impedance matching and attenuation constants, facilitated by interface construction and defect engineering. This work provides new insights and strategies for the development of switchable low/mid-band electromagnetic wave absorption materials and contributes to the advancement of non-carbonized bimetallic MOFs for electromagnetic devices.