Regulating Growth Kinetics of Carbon Nanotubes Toward Efficient Microwave Absorption

Carbon nanotubes (CNTs) show great promise for microwave absorption (MA) due to their excellent electrical conductivity and lightweight properties, which are conferred by the one dimensional hollow tubular structure. However, the ambiguous intrinsic motivations behind the formation of CNTs and the intricate growth processes have resulted in a lack of a systematic methodology for precisely controlling their electromagnetic properties. Herein, a flexible CNTs regulation strategy is designed to develop, with the core focus being the directional growth of carbon atoms and the differential catalysis of metal sources. By improving CNTs growth kinetics, the material achieves effective impedance matching and microwave attenuation, displaying notable magnetoelectric coupling effects. In particular, COMSOL simulations reveal the enhanced dielectric loss contributing to efficient electromagnetic energy conversion. Ultimately, the material demonstrates a minimum reflection loss (RL_min) of -55.85 dB and an effective absorption bandwidth (EAB) of 6.35 GHz at 1.76 mm, which is significantly better than the untreated sample (EAB = 2.02 GHz). This study expands the theoretical foundation of multifactor catalysis in CNTs growth and provides a novel strategy for optimizing the electromagnetic properties of carbon-based materials.