改性低氢超电压镍-硫阴极

MODIFIED Ni-S_x CATHODE WITH LOW HYDROGEN OVERVOLTAGE

在镍－硫镀浴中加入一种催化助剂，制取具有低氢超电压的改性镍－硫阴极。在８０℃，３０％ＮａＯＨ溶液中，电流密度０．４Ａ／ｃｍ＾２时，析氢超电压低至１００－１１０ｍＶ。当电流密度ｉ＜０．２Ａ／ｃｍ＾２时，析氢反应塔菲尔斜率接近２ＲＴ／３Ｆ，可见缓慢电化学脱附为析氢反应限速环节。

A new kind of Ni-Sx coated cathode, which exhibited a low hydrogen overvoltage (100-110 mV at 80℃, at 0.4A/cm2 in 30% NaOH), was prepared electrolytically from nickel-plating bath containing thiourea and a catalyst-accelerator. At the low current density (i <0.2 A/cm2), the Tafel slope fOr hydrogen evolution reaction approached 2RT/3F, suggesting that the slow electrochemical desorption was the rate controlling step for hydrogen evolution.