Preparation of α-MnO2 nanowires through a γ-MnOOH precursor route

In the absence of extra surfactant or template, single crystalline gamma-MnOOH nanowires were prepared directly via a hydrothermal method using KMnO4 and CO(NH2)(2) as starting materials at 120 degrees C for 12 h; and single crystalline alpha-MnO2 nanowires could be obtained after calcining the gamma-MnOOH nanowire precursor in air at 320 degrees C for 5 h. Various measurements were used to characterize the structure, morphology and electrochemical behavior of the resultant products. The urea acted as an important reagent and its participation was believed to contribute to the formation and growth of gamma-MnOOH nanowires and even benefit the improvement of the electrochemical properties of the prepared alpha-MnO2 nanowires. (c) 2006 Elsevier B.V. All rights reserved.