Synthesis of Manganese Oxide Hollow Urchins with a Reactive Template of Carbon Spheres

In this paper, a novel route to synthesize manganese oxide (MnO 2 ) hollow urchins by a reactive template of carbon spheres is described. The formation process of the MnO 2 hollow urchins and the mechanism for the removal of the carbon spheres are suggested. The results of scanning electron microscopy and transmission electron microscopy indicate that MnO 2 shows a hollow‐urchin structure with an average diameter of 1.5 μm and with cavities that are about 250–500 nm in diameter. The X‐ray diffraction pattern indicates that the as‐prepared hollow urchins are γ‐MnO 2 . It has a highBrunauer–Emmett–Teller surface area of 110 m 2 g –1 and a mesoporous structure. In addition, the magnetic properties of the γ‐MnO 2 hollow urchins are investigated. This method opens a way to obtain different morphologies of metal oxides by changing the morphologies of the reactive carbon template. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)