Connecting Kinetics and Mechanisms to Surface Structures on Highly-Oxidized Metal Surfaces in Heterogeneous Catalysis

从化学部的化学催化计划的资金，芝加哥洛约拉大学（LUC）的丹Killelea将探讨在非均相催化氧化反应过程中存在的活性物种，并将探测他们的能量，以促进催化活性金属的氧化表面化学的理解。金属表面上的多相催化氧化反应表面上看起来很简单，但由于表面的异质性，微妙的细节可能占主导地位。这些关键的细节往往是模糊的，使得精确的原子级描述难以捉摸，即使是一个“简单”的反应，如CO氧化为CO2。 阐明这些关于非均相催化反应的原子级细节，预计将有助于促进稀缺资源的利用，并减少对环境有害的副产物的产生。结合表面化学方面，该项目将提供科学研究的机会，代表性不足的社会经济群体在芝加哥公立学校（CPS）通过各种推广工作：高中实验室，图尔斯的LUC设施，和暑期实习计划。 额外的参与和推广工作将包括主办CPS学生会议与招生顾问从当地大学和前往阿贡国家实验室。通过这些努力，来自经济贫困社区的高中生将获得接触科学的机会，并了解新的教育机会和职业。在此奖项下，芝加哥洛约拉大学的Dan Killelea和他的团队正在努力揭示观察到的表面结构与多相催化系统的反应动力学和机制之间的联系。铑金属表面，这是后过渡金属的代表，可重复地制备具有特定的，良好表征的含氧相。缺陷密度和几何形状对表面氧化和化学的影响将使用弯曲的Rh（111）晶体进行系统的探索。来自扫描隧道显微镜（STM）成像的结构数据将使用来自密度泛函理论（DFT）的输入进行解释，该理论还将计算Osub的能量学。所获得的数据将得到辅助表面科学测量的补充。在洛约拉收集的反应性和结构测量将确定CO氧化的进一步研究的表面状态和条件。 这些实验将在莱顿（荷兰）和哥廷根（德国）进行，采用反应分子束散射和速度分辨检测。该项目的成果有望通过提供多相催化氧化反应的动力学和机理方面急需的基本信息来推进催化表面化学，并揭示地下氧在这些工业相关反应中的重要性。该奖项反映了NSF的法定使命，并被认为值得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来支持。

With funding from the Chemical Catalysis program of the Chemistry Division, Dan Killelea of Loyola University of Chicago (LUC) will explore the reactive species present during heterogeneously catalyzed oxidation reactions and will probe their energetics to advance understanding of the oxidative surface chemistry of catalytically active metals. Heterogeneously catalyzed oxidation reactions on metal surfaces seem superficially straightforward, yet subtle details may dominate because of the heterogeneity of the surfaces. These key details are often obscured, rendering accurate atomic-level descriptions elusive for even a ‘simple’ reaction like CO oxidation to CO2. Illuminating these atomic-level details about heterogeneously catalyzed reactions is expected to contribute to advances in the utilization of scarce resources and to a reduction in the generation of environmentally harmful byproducts. In conjunction with the surface chemistry aspect, this project will offer scientific research opportunities to under-represented socioeconomic groups in the Chicago Public Schools (CPS) through various outreach efforts: the high school lab, tours of LUC facilities, and a summer internship program. Additional engagement and outreach efforts will include hosting CPS student meetings with admissions counselors from local universities and trips to Argonne National Laboratory. Through these efforts, high school students from economically disadvantaged neighborhoods will gain exposure to science and learn about new educational opportunities and careers.Under this award, Dan Killelea of Loyola University, Chicago and his team are working to uncover the connection between observed surface structures and reaction kinetics and mechanism for heterogeneous catalysis systems. Rhodium metal surfaces, which are representative of the late-transition metals, are reproducibly prepared with specific, well-characterized oxygenaceous phases. The effects of defect density and geometry on surface oxidation and chemistry will be systematically explored using a curved Rh(111) crystal. Structural data from scanning tunneling microscopy(STM)-imaging will be interpreted using input from density functional theory (DFT), which will also calculate the energetics of Osub. The data obtained will be complemented with ancillary surface science measurements. The reactivity and structural measurements collected at Loyola will identify the surface states and conditions for further study of CO oxidation. These experiments will be conducted in Leiden (Netherlands) and Göttingen (Germany) with the reactive molecular-beam scattering with velocity resolved detection. The results of this project are expected to advance catalytic surface chemistry by providing much-needed fundamental information about the kinetics and mechanisms of heterogeneously catalyzed oxidation reactions and reveal the importance of subsurface oxygen in these industrially relevant reactions.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.