Structurally designed hierarchical carbon nanotubes vertically anchored on elliptical-like carbon nanosheets with enhanced conduction loss as high-performance electromagnetic wave absorbent

Abstract

Designing an effective conducting network to arouse conduction loss is an effective strategy to boost the microwave absorption properties while decreasing the filler weight fraction of absorbers in the matrix. Here, hierarchical carbon nanotubes vertically anchored on elliptical-like carbon nanosheets (Co/C nanosheet@CNTs composite) have been successfully prepared sintering of ZIF-67 in Ar/H2 flow, where the density and length of CNTs on Co/C nanosheet surfaces were effectively controlled by adjusting the heating temperature. When the pyrolysis temperature was 700 °C, high density of curved CNTs were formed on the surface of Co/C nanosheet surfaces and constructed an interconnected network, which resulted in the enhanced conduction loss as irradiated by microwave. Accordingly, it exhibited high-performance microwave absorbing, and the maximum reflection loss reached -51.8 dB GHz and the effective absorbing bandwidth (EAB) achieved 5.9 GHz with only 5 wt% additive in paraffin, which is even superior to the corresponding Co/C nanosheet composite with 10 wt% filler content. This work provides a new direction to fabricate carbon-based absorber with high-performance at low filler loading.