Formation of Mn3O4/C core-shell nanowires and a new Mn-O phase by electron beam irradiation

Carbon shells have been formed on Mn3O4 nanowires under electron beam irradiation in a transmission electron microscope. The microstructure is characterized by transmission electron microscopy (TEM) imaging, electron energy-loss spectroscopy and energy-filtered imaging. Detailed TEM analysis confirms that the outer shell is composed of amorphous carbon with a thickness of 5-20 nm while the core is single crystalline Mn3O4. Electron beam irradiation induces the formation of the carbon shells. A new manganese oxide phase is also found by the transformation of Mn3O4 under the attack of the electron beam.