Birnessite-type Manganese Oxide by Redox Precipitation

Preparation of a birnessite-type manganese oxide, with a layered structure, by redox and hydrothermal reactions is described. A poorly crystalline birnessite is prepared by reacting an aqueous Mn(NO3)2 solution with a NaOH / H2O2 solution at room temperature. A highly crystalline birnessite is obtained by hydrothermal treatment of the poorly crystalline birnessite in a NaOH solution.