物理化学学报 >> 2014, Vol. 30 >> Issue (1): 67-74.doi: 10.3866/PKU.WHXB201311143

电化学和新能源 上一篇    下一篇

NaOH溶液中碱浓度、氧气压力以及温度对Pt电极上氧气还原反应的影响

彭中1,2,3, 阎文艺2, 王少娜2, 郑诗礼2, 杜浩2, 张懿2   

  1. 1 天津大学化工学院, 天津 300072;
    2 中国科学院过程工程研究所, 湿法冶金清洁生产技术国家工程实验室, 北京 100190;
    3 精馏技术国家工程研究中心, 天津 300072
  • 收稿日期:2013-09-24 修回日期:2013-11-13 发布日期:2014-01-01
  • 通讯作者: 杜浩 E-mail:hdu@home.ipe.ac.cn
  • 基金资助:

    国家重点基础研究发展规划项目(973) (2013CB632601)及国家自然科学基金(51274178,51274179,51090382)资助

Effect of Alkali Concentration, Oxygen Partial Pressure and Temperature on Oxygen Reduction Reaction on Pt Electrode in NaOH Solution

PENG Zhong1,2,3, YAN Wen-Yi2, WANG Shao-Na2, ZHENG Shi-Li2, DU Hao2, ZHANG Yi2   

  1. 1 School of Chemical Engineering, Tianjin University, Tianjin 300072, P. R. China;
    2 National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China;
    3 National Engineering Research Center of Distillation Technology, Tianjin 300072, P. R. China
  • Received:2013-09-24 Revised:2013-11-13 Published:2014-01-01
  • Contact: DU Hao E-mail:hdu@home.ipe.ac.cn
  • Supported by:

    The project was supported by the National Key Basic Research Program of China (973) (2013CB632601) and National Natural Science Foundation of China (51274178, 51274179, 51090382).

摘要:

设计制作一种新型耐压电化学池并采用循环伏安(CV)和线性扫描伏安(LSV)技术系统研究了碱浓度、氧气压力以及温度对NaOH溶液中氧气还原反应(ORR)的影响. 研究结果表明,碱浓度、氧气压力和温度对ORR动力学和热力学都有很大的影响. 随着碱浓度增大,ORR过程逐渐由2 电子(生成HO2-)转为1 电子(生成O2-)反应,并且由于氧气溶解度减小和体系粘度增大ORR过程受到很大抑制. 增大压力可以明显增加氧气溶解度,从而从动力学上促进ORR过程;同时计算得到了氧气在不同浓度NaOH溶液中的亨利系数. 随着介质温度升高,由于氧气反应活性增强、扩散系数增大和溶解度减小的共同作用,表现出在给定浓度下存在一最佳温度使得ORR峰电流达到最大.

关键词: 循环伏安, 线性扫描, 氧气还原反应, 亨利系数, 反应活性, 溶解度, 扩散系数

Abstract:

In this study, the influences of alkali concentration, oxygen partial pressure, and temperature on the oxygen reduction reaction (ORR) were examined in detail, using a specially designed electrochemical cell, by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) in NaOH solutions. It was found that the ORR pathway is dependent on the solution alkalinity, and is transformed from a two-electron reduction by forming HO2- in dilute solutions to a one-electron reduction by forming stable O2- in concentrated solutions. The process was significantly suppressed by decreases in the oxygen solubility and increases in the media viscosity. The oxygen pressure had a significant influence on the ORR, substantially promoting the ORR in alkaline solutions as a result of the greatly increased solubility of oxygen in the solutions. We obtained the Henry's constants of oxygen in NaOH solutions with different concentrations. The temperature had a clear dual effect on the ORR, as shown by the existence of an optimal temperature for the ORR in a given alkaline solution. These observations are discussed in terms of the oxygen reaction activity, oxygen solubility, and diffusion coefficient.

Key words: Cyclic voltammetry, Linear sweep voltammetry, Oxygen reduction reaction, Henry’s constant, Reactivity, Solubility, Diffusion coefficient

MSC2000: 

  • O646