Hybrid zeolite imidazolate framework derived N-implanted carbon polyhedrons with tunable heterogeneous interfaces for strong wideband microwave attenuation

Rational manipulation of zeolite imidazolate framework derived carbon microwave absorbers is highly significant, but still remains a challenge. Herein, three kinds of multi-metallic doped N-implanted carbon polyhedrons (NCP), named Mo-NCP, W-NCP and MoW-NCP, with tailored composition and unique structure derived from the pyrolysis of hybrid zeolite imidazolate framework (HZIF) precursors have been fabricated. The architecture can be tuned from rhombic dodecahedral shape for W-NCP and MoW-NCP to chamfered cube shape for Mo-NCP, thereby adjusting their impedance matching and microwave attenuation. With a filler loading of 30 wt%, the obtained absorbers possess not only strong absorption capability, but also wide absorption bandwidth compared with NCP. As the best, the minimum R-L of MoW-NCP is up to -55.6 dB at 11.3 GHz and the absorption bandwidth exceeding -10 dB remarkably reaches as wide as 8.8 GHz with a thickness of 2.8 mm. The excellent performance may be ascribed to the multi-heterogeneous interfaces and smaller metal nanoparticles, resulting in strong dipolar/interfacial polarizations, multiple scatterings, enhanced conduction loss and promoted impedance matching. This study not only broadens the limitation of traditional bimetallic ZIFs, but also pave a novel avenue for the design of novel N-implanted carbon microwave absorbers with tunable chemical composition and multi-heterogeneous interfaces. (C) 2019 Elsevier Ltd. All rights reserved.