A Mechanistic Investigation on the Anodic Deposition of Layered Manganese Oxide

作者：Shamoto Mitsuhiro^*; Mori Katsumasa; Tomono Kazuaki; Nakayama Masaharu

来源：Journal of the Electrochemical Society, 2013, 160(4): D132-D136.

DOI：10.1149/2.040304jes

A kinetic and mechanistic investigation has been carried out on the anodic deposition of layered manganese oxide from aqueous MnSO4 solutions containing chloride salts of potassium, tetraethylammonium (TEA), and cetyltrimethylammonium (CTA) cations. Linear sweep voltammetry and the resulting Tafel plots revealed that electron transfer rate increases with the presence of CTA and with increasing its concentration, which can be ascribed to a decrease in activation energy for the oxidation of Mn2+. Chronoammperometry under diffusion-controlled conditions demonstrated that the steady state current is dependent in magnitude on the type of coexisting cations. The slope of the Cottrell plot decreased with an increase in the size of cations examined, indicating that the reaction is limited by the rate of mass transfer of coexisting cations toward negative charges on the just-deposited Mn oxide. The film grown under the control of diffusion of coexisting cations showed well-crystallized birnessite phase, while that deposited at lower overpotential was X-ray amorphous or low crystalline. Especially, the film grown with CTA was highly crystallized, which can be explained in terms of the low crystalline growth rate at the steady state, as well as its self-assembling property arising from hydrophobic interaction.

• 出版日期2013