Semi-tubular structure of manganese oxide and their electrochemical properties

Tetragonal MnO2 have been successfully synthesized via a facile hydrothermal method with the mixed system of KMnO4 and concentrated nitric acid (HNO3) in distilled water at 140 degrees C for 12 h without the use of any extra surfactant or template. Various measurements such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electronic microscopy (TEM) were used to characterize the sizes, structures, and morphologies of the resultant products, which indicated that the obtained products had semi-tubular structures and high crystallinity. The electrochemical properties of the prepared MnO2 materials were studied using cyclic voltammetry in Na2SO4 aqueous electrolyte, indicating that the prepared material exhibited an excellent capacitance performance. (C) 2011 Elsevier B.V. All rights reserved.