Characterizing and Exploiting the Remarkable Surface Redox Chemistry of Ceria and Its Derivatives

非技术描述：这项研究的目标是推进对二氧化铈（CeO 2）表面行为的基本理解，二氧化铈是一种与各种工业过程和设备相关的技术材料。这些应用包括固体氧化物燃料电池、水分解电解槽、太阳能驱动的热化学燃料生产、化学链燃烧、汽车三元催化剂、有机污染物的光降解和超级电容器。该项目正在进行的方法将材料制备与定义明确的表面终止与先进的表征工具相结合。所获得的见解使精心设计的结构和选择适当的化学物质，以实现卓越的性能。通过为高中生和本科生提供实习机会，以及为研究生提供博士研究机会，将多个层次的学生纳入到这项工作的研究和培训目标中。技术支持：这项研究旨在极大地推进对二氧化铈及其固溶体表面性质的理解。PI建议获得有关内部和暴露的氧化铈表面的氧化还原化学的基础知识，使用定义明确的结构，通过复杂的表征技术支持精致的研究。包括AC。薄膜材料的阻抗谱，以确定作为终止、阳离子化学和应变的函数的表面活性;这种膜的角分辨X射线吸收谱研究，以确定Ce氧化态和关于阳离子物种的局部化学环境;通过熔融膜-衬底结构制备的单独限定的晶界的阻抗研究;以及通过衬底改性产生和操纵具有潜在忆阻特性的垂直排列的纳米结构。该研究利用了校园内广泛的增长和表征工具。学生们在多个层次上参与。研究生参与这项研究的各个方面，并通过在夏季研究和高级论文研究中为本科生提供建议来培养导师技能。此外，高中生通过西北学院参加实验室活动，西北学院是西北大学和埃文斯顿镇高中的合作项目。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。

NON-TECHNICAL DESCRIPTION: The goal of this research to advance the fundamental understanding of the behavior of the surfaces of ceria (CeO2), a technologically relevant material for a wide range of industrial processes and devices. These applications include solid oxide fuel cells, electrolyzers for water splitting, solar-driven thermochemical fuel production, chemical looping combustion, automotive 3-way catalysts, photodegradation of organic pollutants, and supercapacitors. The approach underway in this project combines preparation of materials with well-defined surface termination with advanced characterization tools. The insights gained enable deliberate engineering of structures and selection of appropriate chemistries to achieve exceptional performance. Students at multiple levels are incorporated into the research and training goals of this effort via internships for high school and undergraduate students, as well as doctoral research opportunities for graduate students.TECHNICAL DETAILS: This research aims to dramatically advance the understanding of the surface properties of ceria and its solid solutions. The PI proposes to acquire fundamental knowledge about the redox chemistry of both internal and exposed ceria surfaces using well-defined structures that support exquisite studies by sophisticated characterization techniques. Efforts include A.C. impedance spectroscopy of thin-film materials to determine surface activity as a function of termination, cation chemistry, and strain; angle-resolved X-ray adsorption spectroscopy studies of such films to determine both Ce oxidation state and local chemical environment about cation species; impedance studies of individually defined grain boundaries prepared by fusing film-on-substrate structures; and creation and manipulation of vertically aligned nanostructures, with potential memristive properties, via substrate modification. The research leverages the extensive growth and characterization tools available on campus. Students are engaged at multiple levels. Graduate students participate in all aspects of this research and develop mentorship skills by advising undergraduate students in summer research and senior thesis research. Furthermore, high school students participate in laboratory activities through the Northwestern Academy, a collaboration between Northwestern University and Evanston Township High.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.