Phase interface manipulation by adjusting atomic ordering in metal-organic framework to facilitate microwave absorption

Abstract

Metal-organic frames (MOFs) have been a suitable template for high-performance microwave absorbing materials. However, there has been a lack of effective solutions for the agglomeration and inadequate graphitization transformation of metal nanoparticles after annealing of MOFs. In this work, a simple and safe metal ion exchange method for the experimental process is proposed to etch the surface of Fe MOF (MIL-88) template using nickel metal salts, and the subsequent heat treatment to synthesize Fe-Ni/C nanorods. These fine and uniform metal particles and carefully designed phase engineering have excellent electromagnetic attenuation and good impedance matching. In particular, suitable defects and rich heterogeneous interfaces cause polarization loss to increase, and more obviously, hysteresis loss and natural resonance increase magnetic loss. The experimental results show that the materials have good broadband absorption (6.13 GHz) and high-efficiency loss (−35 dB) microwave absorbing (MA) performance. This work provides a generalized phase interface engineering approach for polymetallic nanorods and provides a useful reference for microwave absorbing materials.