在Pt表面氧降解的电催化过程中产生OH基的证据:后果和应用
Jean-Marc Noël1, Alina Latus, Corinne Lagrost
1Sciences Chimiques de Rennes, UMR CNRS 6226, Université de Rennes 1, Equipe MaCSE, Campus de Beaulieu, 35042 Rennes Cedex, France.
Journal of the American Chemical Society
|January 28, 2012
概括
在电极上的氧降解反应 (ORR) 产生了显著的基 (OH) 基,挑战了传统的2和4电子通路模型. 这一发现揭示了一个新的3电子通路,对燃料电池和传感器有影响.
科学领域:
- 电化学 电化学 电化学
- 表面科学是一门学科.
- 化学反应 化学反应
背景情况:
- 氧降解反应 (ORR) 对能量转化技术至关重要.
- 目前的模型主要考虑2电子 (到H2O2) 和4电子 (到H2O) 路径.
- 了解ORR机制对于优化电化学设备至关重要.
研究的目的:
- 为了研究ORR在金表面的机械路径.
- 识别任何未经记录的ORR产品,如反应性基.
- 评估溶剂和pH对ORR的影响.
主要方法:
- 使用了激进足迹和扫描电化学显微镜 (SECM).
- 在水性和有机溶剂 (DMF,二甲) 中进行实验.
- 在 (Pt) 和金 (Au) 电极上的ORR比较.
主要成果:
- 在Pt.的ORR过程中,已经证明了显著的,以前未经记录的基 (OH) 基生成.
- 确定了一个新的3电子ORR路径 (O2到OH基).
- 特别是在中性/基本pH值和有机溶剂中观察到这种行为.
结论:
- 标准的ORR路径模型往往是不够的.
- 一个涉及OH基形成的3电子路径是重要的ORR路径.
- 反应性OH基的产生对燃料电池,传感器和表面修饰具有广泛的影响.
相关概念视频
Radical Reactivity: Overview
Radicals, the highly reactive species, gain stability by undergoing three different reactions. The first reaction involves a radical-radical coupling, in which a radical combines with another radical, forming a spin‐paired molecule. The second reaction is between a radical and a spin‐paired molecule, generating a new radical and a new spin‐paired molecule. The third reaction is radical decomposition in a unimolecular reaction, forming a new radical and a spin‐paired molecule. These three...
Radical Oxidation of Allylic and Benzylic Alcohols
Activated manganese(IV) oxide can selectively oxidize allylic and benzylic alcohols via a radical intermediate mechanism. Primary allylic alcohols are oxidized to aldehydes, while secondary allylic alcohols yield ketones. The redox reaction of potassium permanganate with an Mn(II) salt such as manganese sulfate (under either alkaline or acidic conditions), followed by thorough drying, yields the oxidizing agent: activated MnO2. While MnO2 is insoluble in the solvents used for the reaction, the...
Radical Autoxidation
The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form hydroperoxide. Autoxidation involves initiation, propagation, and termination steps. Many organic compounds are susceptible to autoxidation—especially ethers in the presence of oxygen, which form hydroperoxides. Even though this reaction is slow, old ether bottles contain small amounts of peroxide, which leads to laboratory explosions during ether...
Heterogeneous Catalysis
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...
Oxidative Cleavage of Alkenes: Ozonolysis
In ozonolysis, ozone is used to cleave a carbon–carbon double bond to form aldehydes and ketones, or carboxylic acids, depending on the work-up.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
Catalysis
Catalysis influences the rate of chemical reactions by providing an alternative reaction pathway with lower activation energy. A catalyst speeds up a reaction, but it is not consumed during the process. The fundamental principle of catalysis is the ability of a catalyst to alter the reaction mechanism, often introducing a more efficient pathway than the uncatalyzed process.In a catalyzed reaction, the catalyst participates directly in the reaction mechanism. It interacts with reactants to form...


