Kinetics of reductive dissolution of colloidal manganese dioxide

Abstract

The temporal characteristics of electron transfer to and proton uptake by colloidal manganese oxides in acidic aqueous solutions have been examined in the time regime of milliseconds to tens of seconds. Time-resolved conductometric measurements coupled with electron-transfer-rate results indicate that electron deposition into the colloidal oxides and protonation occurs simultaneously; i.e., there is no polarization of the colloid during the reduction process. Reduction of the manganese oxides leads to their dissolution with quantitative amounts of Mn(II) produced in the bulk aqueous phase. A detailed examination of both thermal- and radiation-induced dissolution of the metal oxides indicates..