Construction of three-dimensional mesh porous Mo2C/carbon composites by chitosan salting-out for efficient microwave absorption

Constructing conductive network and adjusting impedance matching are effective ways to enhance the microwave absorption capacity of absorbers. However, the experimental procedures for preparing three-dimensional porous network are complex and often involve the use of hazardous agents. We proposed a simple and safe strategy to prepare porous three-dimensional network Mo2C/C composites. The salting-out method can change the aggregation state of chitosan macromolecules and make the free chitosan molecules form a porous three-dimensional network structure autonomously. In addition, the plus-charged amino on chitosan is able to attract minus-charged molybdate ions, which makes the surface of the 3D structured chitosan precursor covered with molybdenum-containing species. The result shows that the porous mesh structure and the heterogeneous interfaces combine to achieve excellent absorption performance of Mo2C/C with effective absorption bandwidth of 5.04 GHz at 1.8 mm. This work demonstrates that salting-out method broadens the idea of porous three-dimensional network electromagnetic wave absorbing materials.