Tuning the Electromagnetic Synergistic Effects for Enhanced Microwave Absorption via Magnetic Nickel Core Encapsulated in Hydrogenated Anatase TiO₂ Shell

Abstract

Owing to tremendous potential applications, hydrogenated TiO2 (H-TiO2) nanomaterial has been considered an important member in the field of microwave absorption. In this paper, a kind of core–shell structured microspheres (MPs) consisting of outer-shell hydrogenated anatase TiO2 (H-A-TiO2) and inner-core magnetic Ni MPs were prepared successfully using a simple method. Experimental results revealed the as-prepared hydrogenated anatase TiO2@Ni (H-A-TiO2@Ni) composite exhibited enhanced microwave absorption property, when compared to pristine anatase TiO2@Ni (A-TiO2@Ni). (1) The minimum reflection loss (RL) of the H-A-TiO2@Ni/wax composite reached −64.2 dB at a thickness of 2 mm, indicating a large absorption efficiency over 99.99%. (2) The H-A-TiO2@Ni showed an effective microwave absorption bandwidth (RL < −20 dB) in a range from 2.2 to 11 GHz. Due to the introduction of core–shell media, coating Ni microspheres with H-A-TiO2 shells not only will be beneficial for impedance matching behavior but also improve the electromagnetic synergistic effects. This study provides a new application area of hydrogenated TiO2 materials as an efficiency energy absorber and opens up a new pathway for design of efficient microwave-absorbing materials.