Redox Processes at the Manganese Dioxide Electrode: I. Constant‐Current Intermittent Discharge

Abstract

The reduction of electrodeposited manganese dioxide (EMD), birnessite, and Bi‐birnessite electrodes was investigated using a constant‐current intermittent discharge technique under conditions where major kinetic effects had been minimized. The results suggested that each type of manganese dioxide underwent a homogeneous reduction followed by a heterogeneous reduction stage. The transition between these reaction mechanisms occurred at a composition that was dependent on the manganese dioxide used. The homogeneous reduction of each electrode was a complex process involving the reduction of ions within the various manganese dioxide structures. The heterogeneous reduction of the electrodeposited manganese dioxide and Bi‐birnessite electrodes resulted in formation of , whereas heterogeneous reduction of the birnessite electrode resulted in formation of .