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旋转圆盘电极(RDE)体系主要用于低溶解度反应物的电极过程动力学研究.在利用RDE技术研究不可逆电极反应动力学时,人们常利用Koutecky-Levich方程排除传质的影响,从总电流估算反应的动力学电流.由于K-L方程是建立在系统满足稳态扩散模型的基础上,实际运用时如果体系偏离稳态扩散,就有可能对估算的动力学参数造成很大误差.本文以氧气在多晶铂电极上的还原反应为例系统地估算了不同氧气浓度与电极转速下的误差,结果表明低氧气浓度与低圆盘转速的情况不满足稳态扩散条件,若此时仍根据K-L方程利用外推法进行分析,误差可达30%.因此作者建议,在RDE体系中利用K-L方程估算动力学参数时,最好忽略低浓度与低转速下的数据,直接使用较高浓度与较高转速下的数据进行计算与分析.
Rotary disk electrode (RDE) system is mainly used for low-solubility reactant electrode process kinetics.In the use of RDE technology to study the irreversible electrode reaction kinetics, people often use the Koutecky-Levich equation to exclude the impact of mass transfer, from the total current estimation Reaction kinetic current.Because the KL equation is based on the system satisfying the steady-state diffusion model, if the system deviates from the steady-state diffusion in actual use, it may cause great error to the estimated kinetic parameters.In this paper, Polycrystalline platinum electrode reduction reaction as an example to systematically estimate the different oxygen concentration and electrode speed error, the results show that the low oxygen concentration and low disc speed does not meet the steady-state diffusion conditions, if still under the KL equation Using extrapolation, the error can be as high as 30%, so the authors suggest that it is best to ignore the data at low and low RPMs when using the KL equation to estimate kinetic parameters in the RDE system, directly using higher and higher concentrations Speed data calculation and analysis.