Synthesis of urchin-like MnO₂/reduced graphene oxide (RGO) composite and their wave-absorbing property

In this paper, urchin-like MnO₂/reduced graphene oxide (RGO) composite were successfully fabricated by a two-step method. The chemical structures, crystalline structures, and microscopic morphology were systematically characterized by Fourier transform infrared spectra (FTIR), x-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). The electromagnetic parameters were measured by a vector network analyzer (VNA). SEM photographs revealed that reduced graphene oxide was firmly attached on the surface of urchin-like MnO₂ with the size in the range of 3–5 μm. The electromagnetic parameters analysis demonstrated that combination of reduced graphene oxide and urchin-like MnO₂ could obviously improve the impedance matching. The maximum reflection loss of urchin-like MnO₂/reduced graphene oxide (RGO) composite is −32.4 dB at 17.2 GHz with a thickness of 1.5 mm, and the reflection loss peaks move to low frequencies with increase of the thickness of the composite sheet. (paper)