A parametric study on the rapid synthesis of one dimensional (1D) α-MnO2 nanowires

In this study, a parametric study was carried out to synthesize 1D alpha-MnO2 nanowires by microwave hydrothermal synthesis. Mixed manganese oxides such as alpha-MnO2/Mn2O3 and alpha-MnO2/beta-MnO2 and 3-MnO2 structures were also synthesized with applying different microwave hydrothermal synthesis conditions such as reaction dwell time, altered between 15 min and 60 min and reaction temperature, altered between 120 degrees C and 160 degrees C, Growth mechanism of alpha-MnO2 and phase transformation to beta-MnO2 was studied by changing such microwave hydrothermal synthesis conditions. The products were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. In order to investigate thermal resistance of the products, TG-DTA analyses were performed under dry air medium. Furthermore, the specific surface area (SSA) and the porosity of the alpha-MnO2 and beta-MnO2 were measured. As a result, when the reaction maintain at 140 degrees C for 30 min, the single crystal alpha-MnO2 structure (SSA = 45.8930 m(2) g(-1) with average pore size of similar to 20 nm) was produced without any impurity. When the reaction time and temperature was further increased to 160 degrees C for 1 h, MnO2 structure completely transformed into beta-MnO2 (SSA = 4.4388 m(2) g(-1) with the average pore size of similar to 15 nm). (C) 2014 Elsevier B.V. All rights reserved.