物理化学学报 >> 2011, Vol. 27 >> Issue (01): 149-155.doi: 10.3866/PKU.WHXB20110126

电化学和新能源 上一篇    下一篇

离子液体添加剂[BMIM]HSO4对锌电积过程析氧反应动力学的影响

张启波, 华一新   

  1. 离子液体冶金重点实验室, 昆明理工大学冶金与能源工程学院, 昆明 650093
  • 收稿日期:2010-09-30 修回日期:2010-11-16 发布日期:2010-12-31
  • 通讯作者: 张启波 E-mail:qibozhang@yahoo.com.cn
  • 基金资助:

    国家自然科学基金(50864009, 50904031)及高等学校博士学科点专项科研基金(20070674001)资助项目

Effect of the Ionic Liquid Additive-[BMIM]HSO4 on the Kinetics of Oxygen Evolution during Zinc Electrowinning

ZHANG Qi-Bo, HUA Yi-Xin   

  1. Key Laboratory of Ionic Liquids Metallurgy, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, P. R. China
  • Received:2010-09-30 Revised:2010-11-16 Published:2010-12-31
  • Contact: ZHANG Qi-Bo E-mail:qibozhang@yahoo.com.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (50864009, 50904031) and Research Fund for the Doctoral Program of Higher Education of China (20070674001).

摘要:

研究了1-丁基-3-甲基咪唑硫酸氢盐([BMIM]HSO4)离子液体对锌电积过程析氧反应的影响. 研究工作借助于动电位极化, 电化学阻抗谱, 扫描电镜和X射线衍射等测试技术. 动电位极化曲线及对应的动力学参数分析表明, [BMIM]HSO4对阳极析氧反应具有催化作用,可提高析氧反应速率常数. 电化学阻抗谱数据表明,[BMIM]HSO4能显著降低阳极析氧电荷传递电阻,在所研究的1.85-2.10 V电位范围内添加5 mg·L-1 [BMIM]HSO4, 电阻值至少降低50%. 此外, 添加剂对阳极表面二次反应具有抑制作用, 其在阳极表面的吸附,阻碍了阴离子的阳极活化位点吸附过程. 电化学测试结果与长时间(120 h)阳极极化后所得阳极表面形貌和结晶取向分析结果相一致. [BMIM]HSO4的添加能有效抑制中间产物β-PbO2的形成,促进铅银电极表面大块且疏松多孔α-PbO2的生成,加速阳极析氧的进行.

关键词: 电化学阻抗谱, 锌电积, 析氧, 离子液体添加剂, 表面形貌

Abstract:

The effect of the ionic liquid additive 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM] HSO4) on the kinetics of oxygen evolution during zinc electrowinning from an acidic sulfate solution was investigated. We used potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy, and X-ray diffraction for this study. Potentiodynamic polarization curves and the corresponding kinetic parameter analysis show that [BMIM]HSO4 has a catalytic effect on oxygen evolution by stimulating the reaction rate constant. Impedance data reveal that [BMIM]HSO4 can markedly reduce the oxygen evolution charge transfer resistance. The addition of 5 mg·L-1 [BMIM]HSO4 obviously decreased the resistance value by at least 50% over the studied potential range from 1.85 to 2.10 V. In addition, the results of the impedance measurements also suggest an inhibition effect of [BMIM]HSO4 on the secondary reactions and this is due to the adsorption of the additive on the anode surface, which decreased the amount of active sites for anion adsorption. All electrochemical results were corroborated with a morphological and orientation analysis of the anodic surface after 120 h of anodic polarization. The addition of [BMIM]HSO4 inhibited the generation of the intermediate product β-PbO2 and it promoted the generation of larger, loose, and porous α-PbO2, which benefited the oxygen evolution reaction.

Key words: Electrochemical impedance spectroscopy, Zinc electrowinning, Oxygen evolution, Ionic liquid additive, Surface morphology

MSC2000: 

  • O646