摘要
报道在1mol／dm3NaOH溶液中于银电极上恒电流还原条件下的电势振荡现象。测定了该振荡反应在电流浓度参数平面上的分合边界图。除了一些出现在上边界处的阻尼振荡以外，还给出了在固定浓度时单调地增加所控电流在边界内产生的典型的电势振荡序列。该振荡现象可用双稳态与正负反馈相偶联来解释，电流扫描和循环伏安实验结果支持这种解释。研究结果表明，除（电）化学反应外，交替为主的扩散和对流物理体质过程在该振荡中起重要作用。
Potential oscillations during S2O8 reduction under galvanostatic conditions in1mol/dm3 NaOH solution on a silver electrode are reported here for the first time. Thebifurcation boundaries were measured in the parameter plane of applied current vs. S2O8concentration. In addition to some interesting damped oscillations occurring on the upperboundaries, a typical oscillation sequence in the boundaries is given which appeared when theapplied current was increased monotonously at fixed S2O8 concentration. This kind ofoscillation has its typical voltammetric characteristics. There is a broad limiting current plateau inthe current-potential curve and the oscillation amplitudes are within that region, and there isa large crossing cycle in the cyclic voltammogram. A model, i. e., a bistability (S2O8 reductionand hydrogen evolution at different potentials) coupled with a negative feedback (depletion ofthe S2O8 surface concentration by reduction under diffuSion control) and a positive feedback(replenishment of the S2O8 surface concentration by convection induced through the hydrogenevolution), has been proposed to explain the oscillations, which was supported by the experimental results of current sweep and cydic voltammetry.
关键词
非线性
现象
电势振荡
还原
过二硫酸根
Nonlinear phenomenon Potential oscillations S2O8 reduction BistabilityFeedbacks
