Achieving Sustainable Ultralight Electromagnetic Absorber from Flour by Turning Surface Morphology of Nanoporous Carbon

Abstract

It is well known that the surface architecture of an absorber has a significant effect on the final electromagnetic (EM) wave attenuation behavior. Herein, a series of nanoporous carbon media with different surface morphologies, including a honeycomb-like structure, three dimension (3D) interrelated network, and irregular lump shape, were obtained by a facile onestep strategy employing the green biomass of wheat flour as the precursor. By optimizing the surface architecture, it is demonstrated that the elaborate 3D interrelated skeleton makes a crucial contribution on the eventual EM absorption performance. At the identical low filler content of only 8 wt %, the nanoporous carbon media with a 3D interrelated skeleton shows the minmium reflection loss (RL min ) of −51 dB, almost 9 times higher than that of the other two nanoporous carbon media with honeycomb-like structures and irregular lump shapes. The corresponding effective frequency bandwidth ( f e , RL exceeding −10 dB) of 4.8 GHz was achieved at a thin thickness of 1.8 mm. Moreover, when slightly changing the mass percentage to 9 wt % in the paraffin matrix, the broad f e region of 6 GHz could cover the whole Ku band. This work provides a facile, sustainable, and low-cost approach for developing ultralight and highly efficient absorption media by means of a renewable biomass as te source, and the derived 3D carbon skeleton displays a great potential for dealing with EM interference.

Biomass carbon derived from pine nut shells decorated with NiO nanoflakes for enhanced microwave absorption properties

“…55,56 Therefore, it is reasonable to suggest that the larger 3 0 and 3 00 values of Ni(OH) 2 /BPC and NiO/BPC can be related to porous structure with high specic surface areas, leading to more migrating charges and interfacial polarization. 57 From Fig. 7(b), a similar tendency of m 0 and m 00 has been observed for the three samples, showing a regular uctuation within a narrow frequency range.…”

Natural iron embedded hierarchically porous carbon with thin–thickness and high-efficiency microwave absorption properties

“…S7c †), the conductive loss of HPCs is enhanced considerably, which is conrmed by the long tails of the Cole-Cole curves for HPCs. 51 It is noteworthy that HPC-2 presents a much straighter Cole-Cole curve with less semicircles than other samples, which implies its stronger conductive loss and may be ascribed to its higher graphitization degree. The greater the graphitization degree is, the stronger conductive loss would be induced.…”

A biomass derived porous carbon for broadband and lightweight microwave absorption

“…However, the resulting network does not allow microwaves to reflect multiple times in gigahertz, because the pore size is much smaller than the wavelength of the microwaves 24 . Nonetheless, the conductive network formed by this 3D structure greatly improves the conductive loss capacity of the sample 25 . The Cole-Cole hemicycles (Fig.…”