Effect of carbonization temperature on dielectric and microwave absorbing properties of cobalt doped mesoporous carbon composites

Co doped mesoporous carbon composites (MC-Co) have been synthesized at different carbonization temperatures via evaporation-induced multicomponent co-assembly strategy. The nanostructures and chemical compositions of MC-Co composites were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM) and X-ray diffraction analysis (XRD), etc. Their electromagnetic and microwave absorption properties were investigated in the frequency ranging from 2 GHz to 18 GHz. By the measurement of electromagnetic parameters and theoretical simulation of reflection loss (RL), the results showed that the minimum RL value of the optimum composite MC-Co-800 reached up to -41.9 dB at 13.5 GHz with a thickness of only 1.80 mm, and the effective absorption bandwidth (< -10 dB) is 4.4 GHz (from 11.4 GHz to 15.8 GHz). This work demonstrated that the optimum carbonization temperature of the obtained composites is 800°C, which is critical to its electromagnetic properties. The excellent microwave absorption properties can be attributed to dielectric loss, Ohmic loss, and characteristic impedance matching. Therefore, the as-synthesized composites could be acted as a candidate of microwave absorber, especially for the light weight demand.