A Study on the Anodic Oxidation of Iodide‐Mediated Sulfur Dioxide Solution
A Study on the Anodic Oxidation of Iodide‐Mediated Sulfur Dioxide Solution
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DOI：
10.1149/1.2100732
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发表时间：
1987-07
影响因子：
3.9
通讯作者：
B. W. Cho;K. Yun;I. Chung
中科院分区：
文献类型：
--
作者：
B. W. Cho;K. Yun;I. Chung
A potentiodynamic method was used to investigate the catalytic effect of potassium iodide on the anodic oxidation of sulfur dioxide solution. The catalytic depolarization effects of potassium iodide are between 0.25 and 0.5 V, depending on electrode materials and current densities. The electrocatalytic oxidation behaviors are different at the platinum and graphite electrodes and are affected by the ensuing chemical reactions. At low electrode potential iodide ions are initially oxidized to iodine and this is followed by the chemical reaction of iodine with sulfur dioxide. At high electrode potential the electrochemical oxidation of iodide progresses to iodate and this is followed by the chemical reaction of iodate with sulfur dioxide. The iodide ions regenerated from the chemical reaction near the electrode surface are available again for oxidation without a supply of iodide ion from the bulk solution.The electrochemical oxidation of sulfur dioxide has attracted attention in energy generation, hydrogen production, sodium sulfate electrolysis, and electrowinning of sulfide ores. Although many studies were devoted to the anodic oxidation of sulfur dioxide (1-5), many questions associated with the oxidation mechanism and the nature of the interaction of sulfur dioxide with the electrode surface have remained unresolved. Recently a few studies were done on the depolarization effect of potassium iodide in the anodic oxidation of sulfur dioxide oxidation (6-8). Matveeva et al.(7) investigated the influence of additions of potassium iodide on the anodic oxidation of sulfur dioxide solution on a platinum electrode. They reported that depending on the concentration ratio of the components, as well as the anode potential, the oxidation of sulfur dioxide could occur both homogeneously and electrocatalyticatly. Matveeva and Kasatkin (8) also reported the catalytic effect of potassium iodide in the anodic oxidation of sulfur dioxide solution on a platinum electrode. They showed that the presence of a fiftyfold exc. ess of sulfur dioxide did not affect the adsorbability of the iodide ion over a wide range of potentials and the electrocatalytic oxidation of sulfur dioxide in the presence of potassium iodide took place on an electrode, the surface of which was covered with a monolayer of specifically adsorbed species. Here we studied the catalytic effect of potassium iodide in the anodic oxidation of sulfur dioxide on the Platinum and graphite electrodes. In order to investigate a mechanism for the electrocatalytic oxidation of sulfur dioxide in the presence of potassium iodide, a potentiodynamic method was performed at various concentration ranges of potassium iodide and sulfur dioxide.
