Preparation and wave-absorbing properties of OPCS@CoFe2O4 core–shell structured wave-absorbing materials with multiple loss mechanisms

Abstract

Great concerns have arisen in wave-absorbing materials due to the increasing number of electromagnetic wave pollution. Porous carbon microspheres (PCS) are considered an excellent wave-absorbing material due to their unique hollow porous structure, but their loss mechanism is relatively single. The aim of present study was to investigate how to enrich the loss mechanism of PCS as well as to expand its absorption bandwidth. In this work, we prepared oxidized porous carbon microspheres (OPCS) with multiple loss mechanisms by chemical etching of PCS using potassium permanganate, on this basis, OPCS@CoFe₂O₄ magnetic composites with core–shell structure and magnetic-dielectric dual-loss mechanism were prepared by one-step hydrothermal method. With the minimum reflection loss (RL_min) of -45.42 dB at the matched thickness of 2.3 mm, and the effective absorption bandwidth (EAB) of 6.3 GHz at the matched thickness of 2.5 mm. Therefore, the present study provides ideas and references for the preparation of wave-absorbing materials with multiple loss mechanisms to realize broadband absorption.