Abstract

Zahraa Hasan Raheem, Abdulkareem Mohammed Ali Al-Sammarraie

As best of our knowledge this is the first time to obtain MnO2 nanostructures with different morphologies without any use of surfactants, templates or acidic conditions. Three different crystal shapes(cross, sheet, and star) of nanostructure pure phase of γ -MnO2 have been successfully synthesized by hydrothermal method at same conditions of temperature ( 160ºC) , time of reaction( 12 h) and the same mole ratio between the oxidizing agent NaClO3 and the Mn+2 precursor (2:1), the only difference was using different Mn+2 precursor (MnSO4.H2O, MnCl2.4H2O and Mn(OAc)2 .4H2O) separately, the prepared samples had been characterized by using field emission scanning electron microscopy (FE-SEM), x-ray diffraction analysis(XRD) FT-IR spectroscopy, Raman spectroscopy, and Brunauer-Emmett-Teller (BET) surface area analysis. The sample with the highest value of surface area was the sample prepared from MnSO4.H2O (9.163 m2/g ) which had a star likeshape. Also the values of De Wolff and micro-twinning defects have been calculated.