物理化学学报 >> 2021, Vol. 37 >> Issue (9): 2007054.doi: 10.3866/PKU.WHXB202007054

所属专题: 燃料电池

综述 上一篇    下一篇

碱性介质中氢氧化和析氢反应机理研究现状

李孟婷, 郑星群, 李莉(), 魏子栋()   

  • 收稿日期:2020-07-21 录用日期:2020-08-14 发布日期:2020-08-19
  • 通讯作者: 李莉,魏子栋 E-mail:liliracial@cqu.edu.cn;zdwei@cqu.edu.cn
  • 作者简介:李莉,1979年生,重庆大学教授、博导,国家自然科学基金委优秀青年基金获得者。2010年于重庆大学获得博士学位。主要从事氢能与燃料电池相关的研究工作
    魏子栋,1963年生,教育部长江学者特聘教授,博导,重庆大学化学化工学院院长。1994年于天津大学获得博士学位。主要从事电化学催化,燃料电池,新能源技术方面的研究
  • 基金资助:
    国家自然科学基金(21822803);国家自然科学基金(91834301);国家自然科学基金(21576032)

Research Progress of Hydrogen Oxidation and Hydrogen Evolution Reaction Mechanism in Alkaline Media

Mengting Li, Xingqun Zheng, Li Li(), Zidong Wei()   

  • Received:2020-07-21 Accepted:2020-08-14 Published:2020-08-19
  • Contact: Li Li,Zidong Wei E-mail:liliracial@cqu.edu.cn;zdwei@cqu.edu.cn
  • About author:Email: zdwei@cqu.edu.cn Tel.: +86-23-65678928 (Z.W.)
    Email:liliracial@cqu.edu.cn +86-23-65678929 (L.L.)
  • Supported by:
    the National Natural Science Foundation of China(21822803);the National Natural Science Foundation of China(91834301);the National Natural Science Foundation of China(21576032)

摘要:

氢氧燃料电池和电解水是实现氢能循环利用的两个重要系统,其中氢氧化反应(HOR)和析氢反应(HER)因在碱性介质中的反应速率较酸性介质中慢2至3个数量级,成为阻碍碱性燃料电池与电解水制氢发展的主要瓶颈。深入研究碱性介质中的HOR/HER机理,探究碱性与酸性电解质中HOR/HER活性差异之根本原因,对发展低温碱性能源转化器件具有重要意义。据此,本文综述了近年来碱性介质中HOR/HER机理的相关解释与推论,如双功能机理、氢结合能(HBE)理论与电子效应,及各观点间存在的争议;并从理论计算的角度,介绍了目前电化学界面的理论模拟方法及其在HOR/HER研究中的应用。由于电化学反应系统的复杂性,实验与理论计算的结合有助于理清HOR/HER的机理以及pH效应,并有望应用于指导设计高活性、高稳定性的HOR/HER催化剂。

关键词: 燃料电池, 电解水, 氢氧化反应, 析氢反应, pH效应, 密度泛函理论, 分子动力学

Abstract:

Hydrogen oxygen fuel cells and water electrolysis serves as two important systems for realizing the recycling of hydrogen energy, which involves two crucial electrochemical reactions, the hydrogen oxidation reaction (HOR) and the hydrogen evolution reaction (HER). The kinetics of HOR/HER in alkaline media is 2 or 3 orders of magnitude slower than that in acidic media, which is the main bottleneck that hinders the development of alkaline membrane fuel cells and alkaline water electrolysis. Thus, clarifying the underlying difference of HOR/HER activity in alkaline and acid electrolytes, and exploring the alkaline HOR/HER mechanism are the significant challenges for widely commercial application of low temperature alkaline energy conversion devices. Here, this paper briefly reviews the related explanations and controversies about the alkaline HOR/HER mechanism in recent years, including bifunctional mechanism, hydrogen binding energy (HBE) theory and electronic effect. The bifunctional mechanism emphasizes the influence of water dissociation and OH adsorption on HER and HOR, respectively, which possesses guiding significance for designing and fabricating composite catalysts. The HBE theory stresses that Had is the key reaction intermediate of HOR/HER, and other external factors, such as electrode potential, pH, ions and so on, affect the HOR/HER mechanism and kinetics by disturbing HBE. HBE is widely considered to be the only activity descriptor of HOR/HER. The electronic effect emphasizes the role of catalysts' composition and reaction intermediates in regulating electronic structure of active sites and changing HOR/HER mechanism. It provides an effective strategy to construct active sites and optimize catalytic activity. In addition, we summarize the theoretical simulation methods of electrochemical interface and their applications in exploring HOR/HER mechanism. In-depth theoretical simulation of HOR/HER mechanism requires the establishment of a more reasonable explicit solvation model on electrode/electrolyte interface and the combination of density functional theory (DFT), ab initio molecular dynamics (AIMD), and microkinetic model, to calculate the electronic structure and the dynamic processes of electrode/electrolyte interface, such as bond breaking and formation, solvent recombination, and proton migration in the electric double layer during reaction process, and then to analyze the HOR/HER mechanism and reaction kinetics under different electrode potentials and electrolytes. The present review is helpful for understanding the ongoing developments of HOR/HER mechanism. And the combination of experiment and theoretical calculation can be employed to explore the pH-dependence of HOR/HER deeply, and design novel HOR/HER catalysts with high activity and stability.

Key words: Fuel cell, Water electrolysis, Hydrogen oxidation reaction, Hydrogen evolution reaction, pH-effect, Density functional theory, Molecular dynamics

MSC2000: 

  • O646