Self-etching template method to synthesize hollow dodecahedral carbon capsules embedded with Ni-Co alloy for high-performance electromagnetic microwave absorption

We employ self-etching template method to prepare an ideal electromagnetic wave (EMW) absorber, which is hollow dodecahedral carbon capsules embedded with Ni-Co alloy particles. The hollow dodecahedral polydopamine (PDA) capsules are constructed by the Ni(OH)(2)/ZIF-67 template automatically etched off during in situ polymerization of Dopamine center dot HCl. N-doped carbon capsules (NCs) embedded with Ni-Co alloy particles (named as Air@NCs(sic)Ni-Co) are obtained after the thermal treatment of Ni(OH)(2)/ZIF-67@PDA. The EMW absorption performance of Air@NCs(sic)Ni-Co has been tuned by different contents of Ni(OH)(2) at 700 degrees C. The minimum reflection loss (RLmin) value is -36.5 dB at 14.77 GHz with a thickness of 2.2 mm. The effective bandwidth (RL < -10 dB) can reach up to 6.55 GHz (from 11.45 to 18 GHz) with a thickness of 2.3 mm, which covers the whole Ku band. Potentially, our study provides a new platform for subtly building hollow dodecahedral carbon capsules embedded with alloy particles using ZIF as self-etching template.