Core-shell architecture of Ni-Co MOF wrapped by a heterogeneous FeBTC@PPy layer for high-performance EMI shielding

Abstract

High-performance EMI shielding of a core-shell nanocomposite of Ni-Co MOF (core) wrapped by a heterogeneous layer of FeBTC MOF and polymeric polypyrrole (PPy) (shell) named Ni-Co/FeBTC@PPy is reported. Herein, the spherical structure Ni-Co MOF was firstly prepared and employed as nucleation sites for polymerization of pyrrole monomer utilizing FeCl3 as an in situ oxidant. Surprising, ionic iron not only played the role of oxidizing agent in the polymerization but was also able to interact with the 1,3,5-benzenetricarboxylate (BTC) organic linker existing in the frame of Ni-Co MOF to generate a new metallic MOF named FeBTC. The simultaneous formation of FeBTC@PPy in the one step polymerization inadvertently enriched both the variety of chemical components and uptake of the specific surface area to the productive nanocomposite. The as-synthesized Ni-Co/ FeBTC@PPy nanocomposite displayed its best shielding efficiency at a weight ratio of 1:3 of Ni-Co MOF: pyrrole monomer, with a maximum shielding SET value of 34.1 dB compared to its value of 20.5 dB and 4 dB for the individual components of PPy and Ni-Co MOF, respectively. The sustainable EM attenuation property of Ni-Co/ FeBTC@PPy can be ascribed mainly to dielectric loss along with interfacial polarization, multiple internal reflection, and multiple scattering.