Low-temperature fabrication of Mn3O4 nanorods by solid-state decomposition of exfoliated MnO2 nanosheets

A novel synthetic route has been developed to prepare manganese oxide nanorods. Using unilamellar manganese dioxide (MnO2) nanosheets as starting materials, we succeeded in obtaining hausmannite (Mn3O4) nanorods. The starting materials, exfoliated manganese dioxide nanosheets, were obtained by intercalation and delamination reaction of the protonic manganese dioxide with the tetrabutylammonium (TBA) cation. The transformation of layered MnO2 nanosheets to Mn3O4 nanorods was achieved by simple pH control and a calcination process, even at a temperature of about 150 °C. Physicochemical characterization and studies of the mechanism of transformation were done using X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), high-resolution transmission electron microscopy (HR-TEM) and field emission scanning electron microscopy (FE-SEM). The components of the reaction and the thermal behavior of the sample were measured by elemental analysis (EA), Fourier transform infrared (FT-IR) spectroscopy and thermal analysis, including thermogravimetry (TG) and differential thermal analysis (DTA).

► A novel synthetic route has been developed to prepare Mn3O4 nanorods.
► This method is based on the exfoliation of layered MnO2 and the solid state decomposition of these MnO2 nanosheets.
► The phase transformation from layered MnO2 to Mn3O4 nanorods can be achieved even at 150 °C.
► The application of the synthetic strategy for other materials would provide a soft-chemical route to an anisotropic nanocrystalline.