One-step fabrication of N-doped CNTs encapsulating M nanoparticles (M = Fe, Co, Ni) for efficient microwave absorption
Abstract
By using a modified non-toxic pyrolysis method, M@NCNTs comprising in-situ formed M nanoparticles encapsulated in nitrogen-doped carbon nanotubes (NCNTs) have been synthesized. Compared to traditional preparation process of M@CNTs (eg: acid-aid treatment to CNTs then decorating M particles onto), this method holds the advantage of free of complicated treatment processes. The M@NCNTs exhibit tightly connected interfaces of M/NCNTs and contain abundant N dopants, which could contribute interfacial polarization and defect-dipole polarization to improving the microwave absorption performance. An intense dielectric relaxation is observed in Fe@NCNTs samples, which further enhances the dielectric loss. As expected, the as-synthesized M@NCNTs composites demonstrate promising candidates in microwave absorption (MWA) application. The minimum reflection loss (RL) of Fe@NCNTs (with 10 wt% loading) is up to -30.43 dB at 3.2 mm, and the effective absorption bandwidth (RL < -10 dB) is as wide as 5.7 GHz which benefits from the neighboring dual absorption peaks induced by the intense dielectric relaxation. Co@NCNTs and Ni@NCNTs also have satisfactory effective absorption bandwidth ∼4.08 and ∼4.72 GHz, respectively. The modified pyrolysis method is low-cost and non-toxic, which could become an industrial technique to synthesize carbonaceous composites for microwave absorption.
- Publication:
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Applied Surface Science
- Pub Date:
- July 2018
- DOI:
- 10.1016/j.apsusc.2018.03.242
- Bibcode:
- 2018ApSS..447..244N
- Keywords:
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- Non-toxic;
- Pyrolysis;
- Heterostructure;
- Fe/Co/Ni@NCNTs;
- Electromagnetic matching;
- Microwave absorption