Enhanced Microwave Absorption Performance of Hollow alpha-MnO2 Nanourchins

Three dimensional (3D) hierarchical nanostructures are expected to provide enhanced microwave absorption properties for nanomaterials. In this report we prepared hollow urchinlike alpha-MnO2 nanostructures and dispersed alpha-MnO2 nanorods via a facile hydrothermal method. The complex permittivity and permeability of the hollow alpha-MnO2 nanourchins/paraffin wax composites with different manganese dioxide loadings were investigated in the range of 2-18 GHz, based on which the corresponding reflection loss were simulated. A minimum reflection loss of -36 dB was obtained from the composites with 50 wt% MnO2 nanostructures. Furthermore, the microwave absorption properties of dispersed alpha-MnO2 nanorods were studied for comparison, which indicate the unique morphol. ogy of the hollow urchinlike nanostructures is of significant effect to their microwave absorption properties.