One-pot synthesis of TiO2–Fe3O4 bimetallic oxides decorated on carbon nanosheets as an efficient photothermal microwave absorber

Microwave absorbers with photothermal property have an important application prospect in extreme environment. However, developing multifunctional microwave absorbers usually requires complex procedures including synthesis process and component design. Here, TiO2–Fe3O4 bimetallic oxides decorated on carbon nanosheets (CNSs/TiO2/Fe3O4) was constructed through a simple one-pot method to apply as a highly efficient photothermal microwave absorber. The synergistic dielectric/magnetic properties of the multi-component composites, together with the visible light absorption of TiO2/Fe3O4, allow CNSs/TiO2/Fe3O4 to efficiently absorb microwave and visible light, and convert them into heat. As a result, CNSs/TiO2/Fe3O4 exhibits an exceptional microwave absorption capability, with a minimum reflection loss (RLmin) of −42.55 dB at a thin thickness of 1.6 mm and a maximum effective absorption bandwidth (EABmax) of 3.52 GHz. Furthermore, it demonstrates a good photothermal response (52.1 °C at 100 mW cm−2) and long-term cycling stability under simulated solar lighting conditions. The mechanisms of the microwave absorption and photothermal conversion were elucidated. In summary, this work presents a simple approach to decorate bimetallic oxides on carbon nanosheets and can provide a mind for designing high-efficiency microwave absorbers with photothermal property. [Display omitted] •This study reported a microwave absorber with photothermal property.•A simple one-pot method to prepare bimetallic oxides decorating carbon nanosheets was developed.•The CNSs/TiO2/Fe3O4 composite achieved excellent microwave absorption performance at an ultrathin thickness.•The CNSs/TiO2/Fe3O4 composite demonstrated strong photothermal conversion capabilities.