CAS-Climate: Electroadsorption Kinetics on Transition Metals: Measurement and Mechanism

在化学系化学结构、动力学和机理A(CSDM-A)计划的支持下，康奈尔大学的金·桑蒂维奇博士和赫克托·阿布鲁尼亚博士正在研究结构和取向明确的过渡金属上表面氢的形成机制。电化学和非线性光谱测量有助于形成跨金属-水界面的质子和电子转移的概念框架。Stivich博士和Abruña博士及其学生研究了金属单晶表面氢的电极电位依赖性形成，因为这一反应代表了氢的形成/产生的第一步，只涉及一个电子和一个质子。该团队还研究了界面电场和表面化学等局部变量对质子和电子转移动力学的影响。非线性光谱分析用于提供金属-水界面的局部电场信息。通过推进电化学反应的机理知识，未来可以设计出从水中高效地产生或放出氢的催化剂。该团队还通过纽约州4-H青年发展计划将电化学和光学科学的概念转化为外展活动。该团队正在为康奈尔大学一年级学生开发有关化学循环的新课程材料。本项目研究铂和钯等定义明确的单晶金属表面上的质子耦合电子转移(PCET)机制。这些多相电化学反应在电催化中很常见，但它们很复杂，因为大多数PCET反应涉及多个质子和电子的转移。该研究小组应用了一种与时间相关的电分析方法和非线性光谱分析来探测表面氢的形成，这只涉及一个质子和一个电子。这些研究考察了单晶金属表面上氢的形成动力学与质子施主和金属化学以及局部电场和表面氧化物的函数关系。利用相敏二次谐波测量来表征电化学反应过程中的局域电场。这些研究促进了对多相PCET电催化机制中分子图景的深入理解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Structure, Dynamics, and Mechanism A (CSDM-A) Program in the Division of Chemistry, Drs. Jin Suntivich and Héctor Abruña of Cornell University are investigating the mechanism of surface hydrogen formation on transition metals with well-defined structure and orientation. Electrochemical and non-linear spectroscopic measurements facilitate the formation of a conceptual framework for proton and electron transfers across the metal-water interface. Drs. Suntivich and Abruña and their students examine the electrode potential-dependent formation of surface hydrogen on metal single crystals because this reaction represents the first step in the evolution/production of hydrogen and involves only one electron and one proton. The team also investigates the influence of local variables such as interfacial electric field and surface chemistry on proton and electron-transfer kinetics. Non-linear spectroscopy is used to provide local electric field information at the metal-water interface. By advancing the mechanistic knowledge of electrochemical reactions, future catalysts that efficiently generate or evolve hydrogen from water could be designed. The team also translates concepts in electrochemical and optical sciences to outreach activities through the New York Stat 4-H Youth Development program. The team is developing new curricular materials on chemical circularity for first year students at Cornell University. This project investigates the proton-coupled electron transfer (PCET) mechanism on well-defined single-crystal metal surfaces such as platinum and palladium. These heterogeneous electrochemical reactions are common in electrocatalysis; however, they are complex because most PCET reactions involve the transfer of multiple protons and electrons. The research team applies a time-dependent electro-analytical method and non-linear spectroscopy to probe surface hydrogen formation, which involves only one proton and one electron. These studies examine the surface hydrogen formation kinetics on single-crystal metal surfaces as a function of proton donor and metal chemistries as well as local electric field and surface oxide. Phase-sensitive second harmonic generation measurements are employed to characterize the local electric field during the electrochemical reaction. These investigations foster a deep understanding of the molecular picture during the heterogeneous PCET electrocatalysis mechanism.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.