Center of Smart Materials and Devices, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing，Wuhan University of Technology, Wuhan 430070, China
In recent years, porous carbon materials derived from biomass have drawn a widely public attention in the electromagnetic wave absorbs field due to their low-cost, environmental friendliness and tunable dielectric loss. In this work, porous spherical carbon (PPSC) was prepared via combining a hydrothermal carbonization and a high temperature calcination process of shaddock peel. The effects of calcination temperature on the morphology, structure and microwave absorbing properties of PPSC were studied. Field emission scanning electron microscope (FE-SEM), thermogravimetric analyzer (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), Raman spectroscopy (Raman), X-ray photoelectron spectrometer (XPS), automatic surface area and porosity analyzer (ASAP) and vector network analyzer (VNA) were used to characterize the structure and test the microwave absorbing performance of the PPSC. The results show that with the increase of temperature, the degree of graphitization and the specific surface area of PPSC increase, and the minimum reflection loss (RL) value and effective absorption bandwidth (EAB) of PPSC calcinated at 700 ℃ are -39.7 dB and 6.1 GHz (95~15.6 GHz) respectively, when the material thickness is 3.0 mm and the frequency is 12.8 GHz. Thus, the PPSC is expected to be a broadband and high-efficiency microwave absorption material.