反氧介质对腐蚀行为和扫描电化学显微镜反应的影响
Emmanuel Mena-Morcillo1, Ali Ebrahimzadeh Pilehrood1, Reza Moshrefi1
1Department of Chemistry, The University of Western Ontario, London N6A 5B7, Ontario, Canada.
Analytical chemistry
|May 22, 2024
概括
使用氧化还原介质 (RMs) 的扫描电化学显微镜 (SECM) 可以误解金属腐蚀. 这项研究揭示了不同的RM如何影响铜和的腐蚀,提供了更定量化的SECM方法.
科学领域:
- 电化学 电化学 电化学
- 材料科学 材料科学 材料科学
- 腐蚀科学 腐蚀科学
背景情况:
- 扫描电化学显微镜 (SECM) 对于研究腐蚀表面的局部电化学反应性至关重要.
- 在反模式下,SECM的一个关键限制是使用外部氧化还原介质 (RMs),这可能会干扰腐蚀测量.
- 区分RM干扰与内在金属反应性是一项挑战.
研究的目的:
- 用多尺度电化学方法研究不同氧化还原媒介 (RM) 对腐蚀基质的影响.
- 分析RMS对铜和电化学行为的影响.
- 通过将RM效应考虑在内,为腐蚀研究开发一个更定量化的SECM应用.
主要方法:
- 使用扫描电化学显微镜 (SECM) 使用两种常见的RM:铁甲醇和六氨 (III) 化物.
- 进行了宏观电化学测量,以评估RM诱导的腐蚀促进.
- 采用有限元建模来分析SECM方法曲线并提取动力速率常数,纠正基质生成物种沉积.
主要成果:
- 发现化可促进铜的腐蚀,通过作为氧化剂.
- 铜的SECM反行为与RM有显著的差异,表明腐蚀反应,而不是被动薄膜,控制了反机制.
- 无源始终显示负反,无论RM,而SECM方法曲线显示由于物种沉积的扭曲.
结论:
- 氧化还原介质的选择显著影响腐蚀表面的SECM测量,可能导致被动行为的误解.
- 了解和建模这些偏差对于使用SECM进行准确的定量分析至关重要.
- 这项工作通过解决氧化还原介质干扰来推进SECM用于可靠的腐蚀研究的应用.
相关概念视频
Ladder Diagrams: Redox Equilibria
449
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+...
449
Voltammetry: Factors Affecting Measurements
151
A current produced due to the redox reactions of the analyte at the working and auxiliary electrodes is called a faradaic current. The reaction can be divided into two types. The current generated due to the reduction of the analyte is called cathodic current, and it carries a positive charge. In contrast, the current produced by analyte oxidation is known as an anodic current, and it has a negative charge. The applied potential at the working electrode determines the faradaic current flow, and...
151
Redox Equilibria: Overview
563
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...
563
Redox Titration: Overview
2.8K
Redox titration is a chemical analysis technique used to determine the concentration of an unknown substance by measuring the electron transfer in a redox (reduction-oxidation) reaction. The process involves gradually adding a titrant with a known concentration of an oxidizing or reducing agent, to the analyte, the solution with an unknown concentration, until reaching the endpoint, which indicates the completion of the reaction between the two substances. Ensuring the analyte is in a single...
2.8K
Redox Titration: Other Oxidizing and Reducing Agents
278
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...
278
Corrosion
24.0K
The degradation of metals due to natural electrochemical processes is known as corrosion. Rust formation on iron, tarnishing of silver, and the blue-green patina that develops on copper are examples of corrosion. Corrosion involves the oxidation of metals. Sometimes it is protective, such as the oxidation of copper or aluminum, wherein a protective layer of metal oxide or its derivatives forms on the surface, protecting the underlying metal from further oxidation. In other cases, corrosion is...
24.0K


