Synthesis of nitrogen-doped graphene wrapped SnO₂ hollow spheres as high-performance microwave absorbers

Nitrogen-doped graphene (NG)/SnO₂ hollow sphere hybrids were synthesized in this work. The chemical composition, crystal structure and morphology have been characterized by FT-IR spectra, XRD, Raman spectra, XPS, SEM and TEM in detail. Reflection loss (RL) values of NG/SnO₂ hollow sphere hybrids less than -10 dB and -20 dB are found in the wide frequency range of 4.5-18 GHz and 5-16.2 GHz within 1.3-3.5 mm, and a minimum RL of -50.3 dB is achieved at 8.6 GHz with the matching thickness of only 2.3 mm. The results indicate that the NG/SnO₂ hollow sphere hybrids with high-performance microwave absorption properties have a promising future in decreasing electromagnetic wave irradiation and interference.