CAREER: Elucidating and Harnessing Metal-Support Interactions using Designer Nanoclusters as Functional Models

许多工业过程都涉及在金属固体表面发生的化学反应。虽然固体材料在将一种化学物质转化为另一种化学物质方面非常有效，但它们不能溶解在液体中，而液体通常是许多反应所必需的，而且会减慢反应速度。模拟固体表面行为的小分子的合成，在加速反应的同时溶解在溶液中，可以改善化学制造。在这个项目中，华盛顿大学化学系的Alexandra Velian教授得到了化学系化学合成项目的支持，准备了应对这一挑战的小分子物种。她的合成目标是小簇原子，其中包含一个暴露的金属位置，可以发生化学反应。这些材料可以溶解在溶液中，因此，它们可以提高它们所促进的反应的选择性、稳定性和可调性。这项研究使人们对单个金属原子上的反应如何发生有了基本的了解。这些知识可以用来确定重要工业规模化学转化的基本步骤。该研究与广泛的外展工作相结合，旨在吸引、支持和留住STEM管道中的第一代、代表性不足或低收入学生，并使他们能够发挥自己的专业潜力。为了实现这些目标，Velian教授为学生提供一对一的指导，通过“化学前沿”（Chemistry Frontiers）这门新课程让学生在本科生涯早期就参与当代研究，并将教师与积极从事研究的学生联系起来。Co6Se8簇的表面功能化被用于合成具有表面嵌入、可调单原子活性位点的纳米簇。这些系统作为金属支撑结构的功能模型。在典型的反应循环中，对控制金属-载体相互作用和邻近活性位点活性如何改变关键中间体反应性的参数进行了评估。这为设计和制备基于表面功能化co6se8纳米团簇的模块化单原子材料提供了一种综合范例。在这些研究工作的同时，Velian博士和她的团队积极致力于促进科学的多样性、包容性和公平性，通过一项倡议，将指导、参与研究和沉浸在研究社区中，重点关注华盛顿大学和大西雅图地区被剥夺公民权的学生。该团队还参与并教育更广泛的科学和非科学社区，了解多相催化在工业过程中的重要性。该奖项反映了美国国家科学基金会的法定使命，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。

Many industrial processes involve chemical reactions that take place on the surface of metallic solids. While solid materials are very effective in converting one chemical to another, they do not dissolve in liquids that commonly are necessary for many reactions and that can slow the reaction speeds. The synthesis of small molecules that mimic the behavior of solid surfaces in speeding up reactions while dissolving in solution could improve chemical manufacturing. In this project Professor Alexandra Velian, Chemistry Department, University of Washington, is supported by the Chemical Synthesis Program of the Chemistry Division to prepare small molecule species that address this challenge. Her synthetic targets are small clusters of atoms that contain an exposed metal site where chemical reactivity can occur. These materials can be dissolved in solution and thus, they may improve the selectivity, stability, and tunability of the reactions they promote. The research gives a fundamental understanding of how reactions at a single metal atom occur. This knowledge then may be used to determine the basic steps in important industrial-scale chemical conversions. The research is integrated with a broad-based outreach effort to engage, enable and retain first-generation, underrepresented or low-income students in the STEM pipeline, and empower them to attain their professional potential. To achieve these goals, Professor Velian provides one-on-one mentorship to students, enables hands on research via “Chemistry Frontiers” - a new course to inform and engage students in contemporary research early in their undergraduate careers, and connects faculty with research active students. The surface functionalization of Co6Se8 clusters is used to synthesize nanoclusters with surface-embedded, tunable single atom active sites. These systems serve as functional models for metal–support constructs. The parameters that govern how metal–support interaction and vicinal active site activity alter the reactivity profile of key intermediates in typical reaction cycles are evaluated. This leads to a synthetic paradigm to design and prepare modular single atom materials from surface-functionalized Co6Se8-based nanoclusters. Concurrent with these research efforts Dr. Velian and her team actively work to promote diversity, inclusion and equity in science through an initiative that integrates mentorship, engagement in research, and immersion into the research community, with a focus on disenfranchised students at the University of Washington and in the greater Seattle area. The team also engages and educates the broader scientific and non-scientific community about the significance of heterogeneous catalysis on industrial 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.