Electrochemical and oxygen desorption properties of nanostructured ternary compound Na_xMnO₂ directly templated from mesoporous SBA-15

A facile one-pot synthesis route has been developed to prepare the structure-controllable ternary compound Na_xMnO₂ by a replication approach using mesoporous silica SBA-15 as template. The material structures were thoroughly investigated by XRD, N₂ sorption, FESEM, TEM, and XPS techniques. The well-defined Na_xMnO₂ nanorods was prepared by the complete manganese source filling into the pore channels of mesoporous silica when the surfactant P123 was extracted with excess ethanol, while layered Na_xMnO₂ nanosheets are obtained by the partial filling of the Mn source into the pore channels where ethanol was not used to extract the surfactant. The Na_xMnO₂ nanosheets can be prepared with a porous structure by controlling the template removing process. Such a layered Na_xMnO₂ nanosheet material has large surface area, more included-oxygen and high reversible specific capacitance (261 F/g), and can be potentially used as high performance electrochemical materials in capacitors and oxygen storage/sensor materials.