Achieving Excellent Electromagnetic Wave Absorption Capabilities by Construction of MnO Nanorods on Porous Carbon Composites Derived from Natural Wood via a Simple Route

Absorbers with light weight, low filler loading, high absorption capacity, and broad absorption bandwidth are highly desirable for electromagnetic (EM) wave absorption application, and extensive efforts in designing excellent performance biomass-derived microwave absorbents using sustainable and renewable materials have been made. Here, for the first time we constructed flexible and high-performance EM-absorbing materials of porous biomass-derived carbon (PBDC) decorated with in-situ grown MnO nanorods (MnOnrs) by a simple process. The chemical composition and microstructural feature of these MnOnrs/PBDC composites are highly dependent on the content of MnOnrs controlled through the concentration of potassium permanganate, and thus their EM properties could be also manipulated. Compared with the pure PBDC, the MnOnrs/PBDC composites exhibited excellent EM wave absorption performance with the minimum reflection loss (RL_min) of-51.6 dB at 10.4 GHz with a thickness of 2.47 mm and a qualified bandwidth of 14.2 GHz with an integrated thickness from 1.00 to 5.00 mm. Notably, the microwave absorption capacity of this new kind of composite is not so susceptible to the content of MnOnrs as those common carbon-based absorbers, which could be attributed to the synergistic effect between PBDC and MnOnrs as well as the hierarchical structure. This work may provide a new guideline for development of biomass as a low-cost, green, and renewable high-performance, carbon-based absorber.