(P42)One-Step Solution Plasma Synthesis of Birnessite-type Nanostructured MnO_2 by the Addition of D-glucose and their Characterizations

摘要

Manganese oxides are one of the most promising transition metal oxide materials for pseudo-capacitor, battery, catalysts, biosensor, magnetic materials and ion-exchanger because of their excellent electrochemical properties. Normally, manganese exists in a variety of stable oxide forms such as MnO, Mn_2O_3, and MnO_2 etc., in which their oxidation states are +2, +3, and +4, respectively [1]. Among them, birnessite-type MnO_2 is a naturally occurring manganese oxide. It exhibits two dimensional layered structure which consists of edge-shared MnO6 octahedra with cations and water molecules occupying the interlayer region. These interesting structural and physical properties of the birnessite have promoted it a variety of proposed applications such as heterogeneous catalyst and secondary battery [2-3]. A variety of synthesis methods have been applied to obtained the nanostructured manganese oxide including hydrothermal, template method, thermal decomposition, sol-gel method and so on. However, multi-step process, time-energy consuming and expensive additional reagents still seem to be obstacles for the commercialization of the nanostructured manganese oxide [4]. In this study, birnessite-type MnO_2 was successfully synthesized in potassium permanganate (KMnO_4) aqueous solution by adding simple-inexpensive sugar D-glucose in the solution before generating glow discharge plasma, at room temperature and atmospheric pressure.