Electrostatics and Structure at Electrode:Electrolyte Interfaces from Nonlinear Optics

电极上的静电和结构：非线性光学的电解质界面

• 批准号: 2153191
• 负责人: Franz Geiger
• 金额: $ 53.7万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2153191&HistoricalAwards=false
• 关键词: Electrostatics; Structure; Electrode; Electrolyte; Interfaces

With support from the Chemical Structure, Dynamics, and Mechanisms A (CSDM-A) program in the Division of Chemistry, Professor Franz Geiger of Northwestern University is using advanced laser methods to study how charged species (ions) and water molecules are arranged in solution near a metal electrode. The textbook model describing this arrangement goes back to the 19th century but describes only the location of the ions and it does not account for their motion. The actual situation is more complicated because the water molecules are arranged differently near the metal surface than they are in the liquid, and the ions move in and out of this interfacial layer near the electrode, called the electrical double layer, or EDL. However, studying the EDL is challenging, as it is only a few nanometers thick, or about 100,000 times thinner than a sheet of paper. Professor Geiger and his students are using laser techniques to directly observe the structure of the water molecules and the ions near the metal surface. Their discoveries could provide fundamental insight that advances technologies ranging from clean energy generation and energy storage to environmental remediation. The project is also contributing to the development of the Nation's science, technology, engineering, and mathematics (STEM) workforce by creating research opportunities for students, and the team is integrating their research into the Evanston high school chemistry curriculum to increase participation in STEM through a science ambassadorship program. By measuring the amplitude and phase of heterodyne-detected second harmonic generation (HD-SHG) signals from electrode:electrolyte interfaces, Professor Geiger and his students can directly probe the structural and electrostatic properties of the Stern and diffuse layers . Using this technique, the team is studying the dynamic exchange of ions between these two components of the electrical double layer that occurs in response to external stimuli (applied potential, pH, electrolyte concentration) and measuring the total interfacial potential drop across the EDL. The HD-SHG methodology is also being implemented in a wide-field microscopy mode capable of imaging spatial variations in the EDL across an electrode surface during electrochemical reactions. By quantifying the Coulombic and non-Coulombic contributions to the interfacial potential drop, and by learning about the structure of interfacial water molecules and ions, they are aiming to improve century-old models for describing electrode processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学系化学结构，动力学和机制A（CSDM-A）计划的支持下，西北大学的Franz盖革教授正在使用先进的激光方法研究带电物质（离子）和水分子如何在金属电极附近的溶液中排列。描述这种排列的教科书模型可以追溯到世纪，但它只描述了离子的位置，而没有解释它们的运动。实际情况更为复杂，因为水分子在金属表面附近的排列方式与在液体中的排列方式不同，离子在电极附近的界面层（称为双电层或EDL）中进出。 然而，研究EDL是具有挑战性的，因为它只有几纳米厚，或者比一张纸薄10万倍。盖革教授和他的学生们正在利用激光技术直接观察金属表面附近的水分子和离子的结构。他们的发现可以提供基本的洞察力，推动从清洁能源发电和能源储存到环境修复的技术发展。该项目还通过为学生创造研究机会，为国家科学，技术，工程和数学（STEM）劳动力的发展做出贡献，该团队正在将他们的研究融入埃文斯顿高中化学课程，以增加参与通过科学奖学金计划。通过测量外差探测二次谐波产生（HD-SHG）信号的振幅和相位，盖革教授和他的学生可以直接探测斯特恩和扩散层的结构和静电特性。使用这种技术，该团队正在研究双电层的这两个组件之间的动态离子交换，该交换响应于外部刺激（施加的电位，pH值，电解质浓度）并测量整个EDL的总界面电位降。HD-SHG方法也被实施在一个宽视场显微镜模式，能够成像的空间变化在整个电极表面在电化学反应过程中的EDL。通过量化库仑和非库仑对界面电位降的贡献，并通过了解界面水分子和离子的结构，他们旨在改进描述电极过程的百年模型。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。