Bimetallic Metal-Organic Framework Derived Pomegranate-like Nanoclusters Coupled with CoNi Doped Graphene for Strong Wideband Microwave Absorption.

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 well-organized micro-nano structure to simultaneously achieve strong and wideband MA performance. Herein, a three-dimensional (3D) hierarchical nanoarchitecture (CoNi@NC/rGO-600) comprising of pomegranate-like CoNi@NC nanoclusters and ultra-small CoNi decorated graphene has been successfully fabricated to broaden absorption bandwidth and enhance 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" is in favor of multiple polarization, magnetic loss, and impedance matching. Moreover, the interconnected 3D CoNi doped graphene not only acts as a bridge to connect pomegranate-like CoNi@NC nanoclusters, but also as a conductive network to supply multiple electron transportation. 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.