Preparation of Co/C Composites Derived from Zn/Co-ZIFs and Their Microwave Absorption Properties

A composite material of Co/N-doped porous carbon was derived from a zeolite imidazolate framework (Zn/Co-ZIF) precursor, which exhibited a controllable microstructure and high specific surface area. In order to study the microwave absorption properties of the composites, the Zn/Co-ZIFs were heat-treated at 930°C in a N 2 atmosphere to obtain the composites, in which Co nanoparticles were distributed uniformly in N-doped porous carbon (Co/C composites). Through N 2 adsorption and desorption testing, the specific surface area of the Co/C composites was about 333.5 m 2  g −1 , and the Barrett−Joyner−Halenda (BJH) pore size distribution was 5.7131 nm, with the majority of pores at mesoporous scale. The microwave absorption properties of Co/C composites with different content were then analyzed, revealing that the Co/C composite with absorbent content of 15 wt.% had the smallest reflection loss (−46.36 dB) at a thickness of 3.1 mm. Based on these results, the Co/C composites not only have the advantages of high specific surface area and special porous structure, but with the appropriate absorbent content, the Co/C composites show excellent microwave absorption performance.