Composition and Structure Design of Co3O4 Nanowires Network by Nickel Foam with Effective Electromagnetic Performance in C and X Band

Effectively attenuating electromagnetic waves in the C and X band through composition and structure design remains a formidable challenge for most absorbing materials. To achieve tunable electromagnetic properties, in this study, one-dimensional (1D) Co3O4 nanowires were successfully grown onto the 3D porous nickel foam (NF) through a facile liquid synthesis. Herein, electromagnetic parameters and microperspective structures have been controlled via changing the hydrothermal temperature, more importantly, the as-prepared composites at 100 °C exhibited prominent microwave dissipation performance in gigahertz. The minimum reflection loss (RL) value reached −41.1 dB at a relatively small matching thickness of 2.1 mm, and the optimal effective bandwidth (RL < −10 dB) of 3.46 GHz at 2.3 mm was also achieved. It should be noted that the RL values of the obtained NF@Co3O4 samples appeared two and three sharp peaks at the thickness of 2.3 mm, 2.5 mm, respectively. Good impedance matching, efficient magnetic loss, dielectric loss, and suitable interfacial polarization should be indispensable for ideal microwave absorption. The porous binary NF@Co3O4 composites not only employ cost-effective raw materials for microwave-absorbing materials in many applications, but also dissipate incident microwave which is in favor of reducing severe electromagnetic pollution all over the world.