Ce^(3+)/Ce^(4+)电对在硫酸和甲磺酸介质中电化学性能的差异  

A Comparative Study of Ce^(3+)/Ce^(4+)Redox Couple on Pt Electrode in Sulfuric Acid and Methanesulfonic Acid

作　　者：李照华[1] 褚有群[1] 马淳安[1] 

机构地区：[1]浙江工业大学绿色化学合成技术国家重点实验室培育基地,浙江杭州310014

出　　处：《电化学》2013年第2期141-145,共5页Journal of Electrochemistry

基　　金：浙江省研究生教育创新基地基金项目(No.1001)资助

摘　　要：采用循环伏安法和线性扫描法研究了硫酸和甲磺酸介质中Ce3+/Ce4+在Pt旋转圆盘电极(RDE)上的电化学性能,初步探索了Ce3+/Ce4+的络合行为,考察了Ce3+反应的交换电流密度、扩散系数以及反应速率常数,比较了两种酸介质中Ce3+在Pt电极氧化的活化能.结果表明,硫酸介质中以Ce4+的络合为主,其平衡电位负移;甲磺酸介质中以Ce3+的络合为主,其平衡电位正移.硫酸介质中Pt电极上Ce3+更容易氧化为Ce4+,硫酸铈(III)的电氧化对温度更为敏感.The electrochemical oxidations of Ce3＋ to Ce4＋ on Pt rotating disk electrode （RDE） in both sulfuric acid and methane- sulfonic acid （MSA） solutions were studied by using cyclic voltammetry and linear sweep voltammetry. The complexing behaviors of Ce3＋/Ce4＋ were preliminarily probed and the exchange current density, diffusion coefficient, as well as reaction rate constant were obtained from Butler-Volmer equation. The activation energies of Ce3＊ oxidation on Pt electrode in two types of acidic media, ob- tained from Arrhenius equation, were also compared. The results indicate that Ce3＋ can be oxidized to Ce4＋ much easier in sulfuric acid than in MSA solutions. The equilibrium potential in sulfuric acid solutions moves negatively due to the predominant complexa- tion of Ce4＋, while that in MSA solutions positively because of the predominant complexation of Ce3＋. The larger values of activa- tion energy for the oxidation of Ce3＋to Ce4＋ on Pt electrode in sulfuric acid solutions suggest that the oxidation of Ce3＋ occurs more readily and the electro-oxidation ofcerous sulfate is more susceptible to temperature.

关 键 词：交换电流密度 扩散系数 反应速率常数 阳极氧化 活化能 

分 类 号：O646.54[理学—物理化学]