Polyol-mediated syntheses of crystalline nanosized manganese oxides.

Potassium-type birnessite and lithium-containing manganese oxides were prepared by the polyol process. The Mn(III)/Mn(IV) mixed-valencies compounds are obtained through the controlled reduction of potassium permanganate in a basic water-diethylene glycol mixture at moderate temperature and very short reaction time, 70 °C and 10 min, respectively. Both solids are quite well crystallized and display high specific surface areas, 137 and 329 m g, respectively. Several polyols with variable chain lengths have been used and it is shown that the nature of the polyol has a marked influence on the textural properties of the birnessite-type solid. [ABSTRACT FROM AUTHOR]