Spontaneously Deposited Manganese Oxide on Acetylene Black in an Aqueous Potassium Permanganate Solution

Manganese oxide was deposited spontaneously on acetylene black by the simple immersion of the acetylene black into a K Mn O 4 aqueous solution via a one-step chemical process for application in electrochemical capacitors. Acetylene black was found to act as the reducing agent and substrate for the heterogeneous nucleation of manganese dioxide in an aqueous K Mn O 4 solution via the in situ monitoring of the reduction potential and pH of the solution and supplementary ultraviolet-visible analysis. The morphology of the acetylene black before and after depositing the manganese oxide was examined using scanning and transmission electron microscopy, which revealed several-nanometer-thick manganese oxide deposits on the acetylene black. X-ray diffraction and Raman spectroscopy showed that the manganese oxide deposited on the acetylene black was the birnessite-type.