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

In the absence of extra surfactant or template, single crystalline γ-MnOOH nanowires were prepared directly via a hydrothermal method using KMnO4 and CO(NH2)2 as starting materials at 120 °C for 12 h; and single crystalline α-MnO2 nanowires could be obtained after calcining the γ-MnOOH nanowire precursor in air at 320 °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 γ-MnOOH nanowires and even benefit the improvement of the electrochemical properties of the prepared α-MnO2 nanowires.