Templated synthesis of hierarchically porous manganese oxide with a crystalline nanorod framework and its high electrochemical performance

A simple approach has been developed to synthesize hierarchically porous MnO2 with a crystalline nanorod framework using mesoporous silica SBA-15 as a template, combined with in situ ion-exchange and surfactant-extraction processes without calcination. XRD, nitrogen adsorption analysis, FE-SEM, TEM, XPS and FT-IR techniques are used for the structural characterization. Such MnO2 materials show a macro-mesoporous hierarchical nanostructure containing large pores of several hundreds of nanometres and mesopores of 3.76 nm with a high surface area of 142 m(2) g(-1). The mesoporous framework of this material is composed of aligned single crystalline MnO2 nanorods of ca. 5-6 nm in diameter and ca. 20-25 nm in length. The electrochemical properties of the prepared MnO2 material were studied using cyclic voltammetry in a mild aqueous electrolyte, which shows that such a MnO2 nanostructure has a very high specific capacitance of 258 F g-1 and a good reversibility due to its favorable phase and hierarchically porous structure as well as high surface area.