Core-shell Ag@C spheres derived from Ag-MOFs with tunable ligand exchanging phase inversion for electromagnetic wave absorption.

ABSTRACT

It has become greatly significant to achieve structurally tunable electromagnetic wave absorption materials (EMAs) derived from metal-organic frameworks (MOFs) via controllably continuous phase inversion. Herein, a series of core-shell Ag@C EMAs were successfully fabricated from Ag-MOFs via adjustable phase inversion. Replacing terephthalic acid (H2BDC) with 2-methylimidazole (Hmim) continuously led to the gradual transformation of Ag-MOF-5 structure into ZIF-L, which determined the crystal and morphological structure of Ag@C EMAs. In addition, due to the optimization of relaxation loss, the minimum reflection loss (RLmin) of S2 reached -50.14 dB with a thickness of 3.0 mm. The EMA derived from the original Ag-MOF had the widest absorption bandwidth (fE) of 5.44 GHz and RLmin of -47.36 dB at only 2.2 mm, respectively. This work can shed new light on the core-shell EMAs derived from phase inversion MOFs, and provide guidance to design novel high-performance EMAs.