在Ni-Fe氧氧化物中追踪催化剂逆氧状态和反应动力学 氧化物演变反应电催化剂:催化剂支持和电解质pH的作用
Mikaela Görlin1,2, Jorge Ferreira de Araújo1, Henrike Schmies1
1Department of Chemistry, Chemical Engineering Division, Technical University of Berlin , Straße des 17. Juni 124, 10623, Berlin, Germany.
Journal of the American Chemical Society
|January 13, 2017
概括
导电支和高pH值通过增强氧化还原行为和活性显著提高氧化氧化氧化氧的电催化剂性能.
科学领域:
- 电化学
- 材料科学
- 催化剂
背景情况:
- 铁氧化是性介质中氧化演化反应 (OER) 的关键电催化剂,对电化学能量转化至关重要.
- 了解导电支和电解质pH等外部因素对催化剂性能的影响对于优化OER至关重要.
研究的目的:
- 研究导电支和电解质pH对Ni-Fe氧化电催化剂的氧化还原行为和OER活性的影响.
- 通过先进的现场光谱和电化学技术阐明控制这些效应的基本机制.
主要方法:
- 在现场进行紫外线光谱电化学,以监测氧化物种.
- 操作电化学质谱 (DEMS) 用于气体演变分析和法拉达效率.
- 在现场冷X射线吸收光谱 (XAS) 用于详细的电子结构分析.
- 循环电压测量以研究氧化还原峰值行为和pH依赖性.
主要成果:
- 导电支和pH> 13显著提高了Ni-Fe氧化的氧化还原活性和OER催化性能 (增加了2-3倍).
- 较高的pH值将OER和Ni氧化潜力转移到正极,并显示了氧化还原峰的非单调的pH依赖性,这表明了特定的质子-电子转移机制.
- 现场紫外线检测证实了高pH的早期氧化,并表明含量增加的混合中心中的分数减少了.
结论:
- 电解质pH和导电支在调节氧化还原化学和增强Ni-Fe氧化的OER活性方面发挥着至关重要的作用.
- 这些发现为质子-电子转移过程和Fe在Ni-Fe氧化电催化中的作用提供了新的机械洞察力.
- 这项工作为优化性OER催化剂的电化学能源应用提供了更深入的理解.
相关概念视频
01:23Redox Equilibria: Overview
1.7K
A reduction-oxidation reaction is commonly called a redox reaction. In a redox reaction, electrons are transferred from one species to another rather than being shared between or among atoms. The reducing agent or reductant is the species that loses electrons and gets oxidized in the process. The species that gains electrons and gets reduced in the process is the oxidizing agent or oxidant. Redox reactions are represented as two separate equations called half-reactions, where one equation...
1.7K
03:11Oxidation-Reduction Reactions
76.6K
Oxidation–Reduction Reactions
76.6K
01:24Redox Reactions
59.2K
Oxidation-reduction or redox reactions involve the transfer of electrons from one molecule or atom to another. When an atom gains an electron, another atom must lose an electron, meaning oxidation and reduction must occur together. Since the redox occurs in pairs, the atom that gets oxidized is also called the reducing agent or reductant, and the atom that is reduced is also called the oxidizing agent or oxidant. A straightforward way to remember the definitions of oxidation and reduction is...
59.2K
01:27Redox Reactions
1.3K
Redox reactions are vital biochemical processes that underpin energy metabolism in cells. These reactions involve the transfer of electrons between molecules, occurring in tandem as oxidation and reduction. Oxidation refers to the loss of electrons, while reduction denotes their gain. This coupling ensures the seamless flow of electrons through metabolic pathways. For example, in bacterial metabolism, glucose undergoes oxidation to carbon dioxide, while oxygen is simultaneously reduced to...
1.3K
01:30Ladder Diagrams: Redox Equilibria
835
Ladder diagrams are useful tools for understanding redox equilibrium reactions, especially the effects of concentration changes on the electrochemical potential of the reaction. The vertical axis in the redox ladder diagrams represents the electrochemical potential, E. The area of predominance is demarcated using the Nernst equation.
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
835
01:26Redox Titration: Other Oxidizing and Reducing Agents
1.5K
Besides iodine, other oxidizing or reducing agents can serve as titrants in redox titrations. Common oxidizing titrants include KMnO4, cerium(IV), and K2Cr2O7. The choice of oxidizing titrants depends on factors like stability, cost, analyte strength, and reaction rate between the analyte and titrant. KMnO4 is a strong oxidizing titrant that reduces from Mn(VII) to Mn(II) in a highly acidic solution, simultaneously oxidizing the analyte to a higher oxidation state. In this case, KMnO4 acts as a...
1.5K