High temperature and low current density synthesis of Mn3O4 porous nano spheres: Characterization and electrochemical properties

Uniform and single-crystalline Mn3O4 nano-spheres were synthesized by cathodic electrodeposition at high temperature (80 °C) and low current density (0.25 mA cm−1) on steel electrode. Further the annealed samples were characterized for their structural and morphological properties by means of X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) studies. TEM and SEM images showed that particles have spherical shapes and the average diameter size was about 50 nm. Formation of Mn3O4 compound was confirmed from FTIR studies. The XRD pattern showed that the Mn3O4 exhibit tetragonal hausmannite structure. The results of N2 adsorption-desorption analysis indicated that Mn3O4 nano–sphere has BET surface area of about 177.6 m2 g−1 and average pore diameters of 3 and 4 nm. The possible formation mechanism of Mn3O4 nanostructures has been discussed. The supercapacitive properties of Mn3O4 sample in 0.5 M Na2SO4 electrolyte showed maximum supercapacitance of 235.4 Fg−1 at scan rate 10 mV s−1. Coulumbic efficiency could be kept about 90% during 1000 cycles at 10 mV s−1.