Microwave-Assisted Synthesis of N-Doped Graphene-Wrapped MnO2 Nanoflowers

Abstract

Nitrogen-doped graphene wrapped MnO2 nanoflowers (N-G-MnO2) have been successfully synthesized via a simple scalable method. N-graphene nanosheets were prepared first by ball milling graphite and urea followed by mixing of N-graphene and MnO2 nanoflowers that was microwaved for only a few minutes to form N-G-MnO2 nanoflowers. The self-assembled layer of N-G-MnO2 nanoflowers over a silicon wafer was prepared using a reverse meniscus convective self-assembly technique. The as-prepared samples were characterized by scanning electron microscope (SEM), x-ray diffraction (XRD), transmission electron microscope, Raman and Fourier transform infrared spectroscopy. The final product of this process revealed the successful formation of N-G-MnO2 with great uniformity and high purity. SEM investigations reveals good dispersion and uniform distribution of N-G-MnO2 nanoflowers over a wide area. The addition of humic acid was found to be a crucial factor for the formation of the flower morphology. XRD phase studies show the formation of birnessite-MnO2 structure. This cost-effective, eco-friendly, and scalable process could be used for industrial applications such as energy storage materials.