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

在化学系化学结构、动力学和机制A（CSDM-A）项目的支持下，康奈尔大学的Jin Suntivich和Héctor Abruña博士正在研究具有明确结构和取向的过渡金属表面氢形成的机制。电化学和非线性光谱测量促进了质子和电子在金属-水界面上转移的概念框架的形成。Suntivich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，因为该反应代表了氢演化/产生的第一步，仅涉及一个电子和一个质子。该团队还研究了局部变量（如界面电场和表面化学）对质子和电子转移动力学的影响。非线性光谱用于提供金属-水界面处的局部电场信息。通过推进电化学反应的机理知识，可以设计出从水中有效产生或释放氢气的未来催化剂。该团队还通过纽约Stat 4-H青年发展计划将电化学和光学科学的概念转化为外联活动。该团队正在为康奈尔大学的一年级学生开发新的化学循环课程材料。本计画主要研究在铂、钯等单晶金属表面上的质子耦合电子转移机制。这些非均相电化学反应在电催化中很常见;然而，它们是复杂的，因为大多数PCET反应涉及多个质子和电子的转移。该研究团队应用时间相关的电分析方法和非线性光谱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氢的形成动力学，作为质子供体和金属化学性质以及局部电场和表面氧化物的函数。相敏二次谐波产生测量被用来表征电化学反应过程中的局部电场。这些研究促进了对多相PCET电催化机制中分子图像的深入理解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值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.