Metal-organic framework derived cobalt phosphosulfide with ultrahigh microwave absorption properties

Nanostructure composites of ferromagnetic materials embedded in nanoporous carbon (NC) derived from metal-organic frameworks (MOFs) have attracted enormous attention due to their potential application in many fields, such as microwave absorption, energy storage, and conversion. The rational design of nanocomposites holds a determinant factor for overcoming the challenges involving the microwave absorption performance. Herein, CoS₂/NC, CoP/NC, and CoS_2-xP_x/NC with a rhombic dodecahedral structure have been successfully fabricated by using the template cobalt-based MOFs (ZIF-67). A morphology analysis indicates that ferromagnetic nanoparticles are embedded in NC matrix. It is obvious that the rhombic dodecahedron can be maintained after the phosphorization and sulfurization of Co/NC derived from the thermal decomposition of ZIF-67. The microwave absorption performance can obviously be improved by the phosphorization and sulfurization of Co/NC. CoS_2-xP_x/NC exhibits an excellent microwave absorption property and the minimum reflection loss (RL) of CoS_2-xP_x/NC can reach -68 dB at 14.6 GHz with a thickness of 1.5 mm. An RL value less than -10 dB can be achieved in the microwave frequency range of 12.7-17.3 GHz (4.6 GHz) with a thickness of 1.5 mm for CoS_2-xP_x/NC. This article offers a novel way to fabricate cobalt-based materials/carbon composites for an excellent microwave absorber.