摘要
用恒电流法测试在２２～７０℃之间电解３０ｗｔ．％ＫＯＨ水溶液时Ｎｉ阳极的稳态极化曲线以及该过程的交换电流密度ｉ０，Ｔａｆｅｌ斜率ｂ，传递系数β和不同电流密度下的析氧过电位随电解温度的变化关系结果发现：４０℃是各参量随温度变化的一个突出变点，４０℃以下，高过电位区的Ｔａｆｅｌ斜率达１２０ｍＶ以上，低过电位区的反应活化能Ｅａ为７９．８８ｋＪ／ｍｏｌ，而４０℃以上时，上述两参数分别为６０～７０ｍＶ和５５．３２ｋＪ／ｍｏｌ．
The steady_state polarization curves of oxygen evolution were measured at temperatures between 22～70 ℃ on Ni electrode in 30 wt.% KOH solution by galvanostat methode. The exchange current densities, Tafel slopes and transfer coefficients were studied. It was found that 40 ℃ is a special temperature, near which the kinetic parameters change abrupdy. The Tafel slopes for oxygen evolution reactions at higher overpotentials change from more than 120 mV to about 70 mV when the temperature raises to 40～70 ℃ from 22～35 ℃. Simultaneously, the heat of activation is changes from 79.88 kJ/mol to 55.32 kJ/mol. Moreover, the -(η/Τ) i and how it changes with lg i are quite different in the two temperature ranges: The slope of -(η/Τ) i vs. lg i is 4.63 at the lower temperatures, while at the higher temperatures it is only -0.455.
出处
《电化学》
CAS
CSCD
1998年第4期428-433,共6页
Journal of Electrochemistry
关键词
镍电极
氧析出反应
析氧行为
氢氧化钾溶液
Nickel electrode, Oxygen evolution reaction, Steady_state polarization
