Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (1): 67-74.doi: 10.3866/PKU.WHXB201311143

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

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).

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