In Situ Dual-Template Method of Synthesis of Inverse-Opal CoO@TiO with Wideband Microwave Absorption.

A unique porous TiO with CoO nanoparticles anchored in (CoO@TiO) is prepared by a dual-templating method for promoting electromagnetic microwave absorption (EMA). The as-prepared CoO@TiO possesses a three-dimensional (3D) ordered macroporous TiO skeleton and plenty of mesopores, as well as small CoO nanoparticles that coexisted in the macropore walls of the TiO skeleton. The introduction of CoO can increase the magnetic loss as well as suppress impedance mismatch, resulting in the regulation of the EMA performance. The synergetic effect of the TiO porous framework and CoO nanoparticles with proper ratio promote microwave absorption performance. Therefore, CoO@TiO-2 with 25 wt % CoO nanoparticles content displays a strong and ultrawide effective absorption band (EAB) performance. The CoO@TiO-2 presents a strong reflection loss of -53.9 dB at 2.95 mm. Moreover, it obtains a super broad EAB of ∼12.5 GHz at 5.0 mm. This dual-templating approach for a well-controlled porous structure could be a facial strategy for the development of high-performance electromagnetic wave absorbers.