Hydrogen Evolution on the Surface of a Chromium Electrode at High Current Density
大电流密度下铬电极析氢行为

At the high current density of 7.5~20 A/dm2 for chromium electrowinning, the polarization curves of hydrogen evolution on a chromium electrode at the conditions of 30~55oC and pH=2.1~2.5 were obtained to explore the electrochemical process of hydrogen evolution at high current density. It was found that the potential of hydrogen evolution decreases with the increase of temperature and decrease of pH. The polarization curves are shifted toward more negative when adding (CH3)3NC16H33Br (CTMAB) in the sulfate solution. It is shown that the CTMAB can suppress hydrogen evolution moderately. When electrowinning chromium in the solution with 20 mg/L CTMAB, the current efficiency is increased by 8.1%. A series of data of over-potential on the chromium electrode at different temperatures with pH=2.1 was obtained. All the Tafle plots at different temperatures pass through a common point with the coordinate lgi equal to 1.72 and over-potential to 1.35 V.