Preparation and characterization of rod-shaped MnO2 crystal

Rod-shaped MnO₂ crystal was synthesized by a new route, the sample was a multicrystal with the mixture of α- and γ-MnO₂. From TEM results, it could be seen that the sample has a length of 250-350 nm and a diameter of 15-25 nm. The ratio of length to the diameter could reach more than 15:1. In the preparation process, the KMnO₄ was used as oxidant and MnCl₂ was the manganese source. The polyethylene glycol (PG) was added as the dispersant and the high molecular weight polyacrylamide (PAM) was introduced at the same time. When the reaction finished, the product was treated with steam for 3 h and then the rod-shaped MnO₂ crystal was obtained. The crystal was characterized by X-ray diffraction (XRD), electron diffraction (ED), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM).