posted on 2020-04-01, 13:00authored byXueqing Xu, Feitian Ran, Zhimin Fan, Zhongjun Cheng, Tong Lv, Lu Shao, Yuyan Liu
Metal–organic
frameworks (MOFs) featuring high porosity
and tunable structure make them become promising candidates to fabricate
carbon-based microwave absorption (MA) materials to meet the requirements
of electronic reliability and defense security. However, it is challenging
to rationally design a well-organized micro-nanostructure to simultaneously
achieve strong and wideband MA performance. Herein, a three-dimensional
(3D) hierarchical nanoarchitecture (CoNi@NC/rGO-600) comprising pomegranate-like
CoNi@NC nanoclusters and ultrasmall CoNi-decorated graphene has been
successfully fabricated to broaden the absorption bandwidth and enhance
the absorption intensity. The results confirm that the bimetallic
MOF CoNi-BTC-derived pomegranate-like CoNi@NC nanoclusters with porous
carbon shell as “peel” and sub-5 nm CoNi nanoparticles
as “seeds” favor multiple polarization, magnetic loss,
and impedance matching. Moreover, the interconnected 3D CoNi-doped
graphene acts not only as a bridge to connect pomegranate-like CoNi@NC
nanoclusters but also as a conductive network to supply multiple electron
transportation paths. Consequently, the optimized CoNi@NC/rGO-600
exhibits extraordinary MA performance in terms of wide bandwidth (6.7
GHz) and strong absorption (−68.0 dB). As an effective strategy,
this work provides a new insight into fabricating hierarchical composite
structures for advancing MA performances and other applications.