Facile morphology controllable synthesis of zinc oxide decorated carbon nanotubes with enhanced microwave absorption

The microscopic morphology of the composites has a great influence on their microwave absorbing (MA) performances. However, it remains a challenge to achieve morphology control through a facile way when preparing composites of carbon nanotubes and zinc oxide. In this work, a simple and room-temperature approach is proposed to synthesize zinc oxide/carbon nanotubes (CNT/ZnO) nanocomposites with different microstructures. Changing the type of solvent can lead to different microstructures of CNT/ZnO nanocomposites. This is mainly because of the different ion molar ratio to Zn²⁺ and OH^- in the reaction solution. Besides by adjusting the content of CNT, the microwave absorbing properties of the obtained CNT/ZnO nanocomposites can be controlled. When the CNT content is 10% mass fraction, the minimum reflection loss (RL) of CNT/ZnO-E nanocomposite can reach − 55.42 dB at a thickness of 3 mm. With the increasing weight ratio of CNT, the degree of disorder in the material and the number of the defects increase, 3D conductive networks are easier to form, resulting in the enhanced polarization loss and conductive loss. However, excessive CNTs will cause excessive current induced which is not conducive to electromagnetic wave absorption.