Reduced Graphene Oxide/Titanium Dioxide Nanocomposites via Atomic Layer Deposition for Microwave Absorption

The reduced graphene oxide/titanium dioxide (RGO/TiO2) nanocomposites were first prepared by the atomic layer deposition (ALD) method for microwave absorbing. The deposition content of TiO2 nanoparticles on the RGO surface was precisely adjusted by manipulating the number of ALD cycles. On the one hand, the appropriate TiO2 nanoparticles can precisely regulate the impedance matching to obtain lightweight nanocomposites. On the other hand, the interfaces between RGO and TiO2 can be regulated to retain active sites when the number of ALD cycles is low. Thus, impedance matching and attenuation ability of the composites could be regulated. The microstructure of RGO/TiO2 nanocomposites was characterized by SEM, TEM, and XPS, and the relationship between microstructures and microwave absorption properties was also investigated in detail. The RGO/TiO2 nanocomposites possessed high microwave attenuation ability due to the polarization loss and conduction loss. The nanocomposites, with appropriate impedance matching and high attenuation constant, displayed outstanding microwave absorption performance. When the number of ALD cycles was 150, the maximum reflection loss of the RGO/TiO2 nanocomposite could reach −41.3 dB, and its maximum effective absorption bandwidth reached 4.88 GHz, which almost covered the Ku band. This study implied that the RGO/TiO2 nanocomposite has potential application in microwave absorption.