Mesoporous carbon hollow microspheres with tunable pore size and shell thickness as efficient electromagnetic wave absorbers

Carbon hollow microspheres with a uniform mesoporous shell (PCHMs) were designed and fabricated using a template-assistant method followed by a pyrolysis-etching process. Through tuning the pyrolysis temperature, PCHMs with various pore size and shell thickness can be obtained. In particular, the PCHMs carbonized at 650 degrees C (PCHMs-650) are composed of a mesoporous shell (thickness: 52 nm) and an interior void of 153 nm, endowing the materials with large surface area of 925.9 m(2)/g. The unique core-shell structure generated by carbon shell and void core is critical for the attenuation capability of EM energy. The composites containing 20 wt% PCHMs-650 exhibit favorable microwave absorbing performance with the minimum reflection loss (RLmin) of -39.4 dB at ]3.6 mm. The broadest effective absorption bandwidth (EAB) can extend to 5.28 GHz (9.68-14.96 GHz) at only 2.6 mm. It is believed that PCHMs can be used as a promising absorber with light-weight, impressive bandwidth and strong absorption efficiency.