在化学调节的有序金属间催化剂中促进完全电子转移的氧降低反应的现场机制见解
Soumi Mondal1,2, Debabrata Bagchi1,2, Mohd Riyaz1,2
1New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
Journal of the American Chemical Society
|June 24, 2022
概括
这项研究介绍了Pt0.2Pd1.8Ge,一种新型催化剂,可显著增强性燃料电池中的氧降解反应 (ORR) 动力学. 与催化剂相比,它显示出更高的稳定性和活性.
科学领域:
- 电化学
- 材料科学
- 催化剂
背景情况:
- 性燃料电池由于缓慢的氧降解反应 (ORR) 动力学而面临限制.
- (Pt) 催化剂虽然活跃,但在性介质中具有不良的稳定性和缓慢的动力学.
- 现有的Pt替代催化剂往往缺乏长期稳定性.
研究的目的:
- 为了设计一个高度稳定的,未经探索的有序金属间结构,Pd2Ge.
- 通过选择性取代Pt来增强活动场所的电子环境.
- 为了克服性ORR的动力限制.
主要方法:
- Pt0.2Pd1.8Ge金属间化合物的合成和表征.
- 电化学评估包括半波潜力 (E1/2) 和质量活性 (MA) 的测量.
- 加速降解试验 (ADT) 和旋转圆盘电极 (RRDE) 实验.
- 在现场里叶变换红外光谱 (FTIR),X射线吸收光谱 (XAS) 和X射线光电子光谱 (XPS) 进行机械洞察.
主要成果:
- Pt0.2Pd1.8Ge表现出0.95V的高半波电位 (E1/2),超过商业20%的Pt/C.
- Pt0. 2Pd1. 8Ge的质量活性 (MA) 是Pt/ C (320 mA/ mgPt) 的3.2倍.
- 在5万个ADT循环后,催化剂保持了性能,显示出极好的稳定性.
- RRDE和光谱分析证实了抑制的2e-路径,最大限度地减少过氧化 (H2-O2) 的产生和促进4e-转移.
结论:
- 在Pd2Ge中选择性的Pt替代产生了性燃料电池的高活性和稳定的ORR催化剂.
- Pt0.2Pd1.8Ge为传统的基于Pt的催化剂提供了一个有希望的替代品.
- 增强的稳定性和活性归因于有利的电子结构修改和抑制的H2O2形成.
更多相关视频
09:02Synthesis of Platinum-nickel Nanowires and Optimization for Oxygen Reduction Performance
Published on: April 27, 2018
7.9K
06:53Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
2.1K
相关概念视频
Catalysis
27.5K
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
27.5K
Introduction to Mechanisms of Enzyme Catalysis
8.7K
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes...
8.7K
Redox Equilibria: Overview
639
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...
639
Reaction Mechanisms
26.3K
Chemical reactions often occur in a stepwise fashion, involving two or more distinct reactions taking place in a sequence. A balanced equation indicates the reacting species and the product species, but it reveals no details about how the reaction occurs at the molecular level. The reaction mechanism (or reaction path) provides details regarding the precise, step-by-step process by which a reaction occurs.
For instance, the decomposition of ozone appears to follow a mechanism with two steps:
For instance, the decomposition of ozone appears to follow a mechanism with two steps:
26.3K
Multi-Step Reactions
7.5K
Chemical reactions often occur in a stepwise fashion involving two or more distinct reactions taking place in a sequence. A balanced equation indicates the reacting species and the product species, but it reveals no details about how the reaction occurs at the molecular level. The reaction mechanism (or reaction path) provides details regarding the precise, step-by-step process by which a reaction occurs. Each of the steps in a reaction mechanism is called an elementary reaction. These...
7.5K
Thermal and Photochemical Electrocyclic Reactions: Overview
2.4K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
2.4K
