CAS: Linking bulk composition and structure to the dynamic active surface in OER

许多化学过程依赖于催化材料，通过促进催化剂表面的化学反应来提高过程效率和产品选择性。例如，水电解——将水分解成氢气和氧气——需要氢气和氧气释放反应（HER和OER）的催化剂。催化剂设计历来是由对散装材料特性的理解驱动的；然而，反应发生的表面在反应环境中会发生巨大的变化。该项目探索钙钛矿材料的体积和表面催化性能之间的关系，作为通过电催化水分解高效、可持续制氢的途径，从而实现氢经济。此外，该项目还开发了相关课程，旨在培训学生掌握用于能源转换和储存的电化学装置，同时促进向代表性不足的群体提供服务。该项目阐明了钙钛矿材料体模板和表面性质之间的关系，在电催化反应期间和之后。所得数据将指导原子水平上的材料设计。将确定功能界面转换的主要驱动因素-不仅考虑材料成分（和相关的电子结构）的作用，还考虑由底层晶格施加的应变产生的二维模板，以及来自移动阳离子和氧空位等缺陷存在的三维模板。此外，还将研究本体和表层之间电荷转移的大小和长度尺度。该项目将结合原子精密材料合成与表面敏感元素特定光谱和显微镜，考虑（001）取向钙钛矿氧化物家族的析氧反应（OER）。总之，这些研究将建立对材料界面动态演变的理解和最终控制，再加上它们在OER中的活性和稳定性，使材料设计能够通过创新的物质组装来利用这个界面区域。本提案中的工作将进一步纳入实践学习活动和开放式项目中，这些项目以本科课程中用于能量转换和存储的电化学装置为中心，并向代表性不足的群体推广。该项目由化学、生物工程、环境和运输过程（CBET）部门的催化项目和化学部门的化学催化项目共同资助。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 chemical processes rely on catalytic materials that enhance process efficiency and product selectivity by promoting chemical reactions at the catalyst surface. For example, water electrolysis – the splitting of water into its constituent hydrogen and oxygen gases – requires catalysts for both the hydrogen and oxygen evolution reactions (HER and OER). Catalyst design has historically been driven by an understanding of bulk material properties; however, the surface where reactions occur can change dramatically in the reaction environment. The project explores relationships between bulk and surface catalytic properties of perovskite materials as a pathway to efficient, sustainable, hydrogen production via electrocatalytic water splitting – thereby enabling the hydrogen economy. Additionally, the project develops related courses designed to train students in electrochemical devices for energy conversion and storage, while promoting outreach to underrepresented groups. This project illuminates relationships between perovskite material bulk template and surface properties, during and following electrocatalytic reactions. The resulting data will guide materials design at the atomic level. The primary drivers of transformations at functional interfaces will be identified - considering not only the role of materials composition (and associated electronic structure), but also two-dimensional templating from strain imposed by the underlying lattice, and three-dimensional templating from the presence of defects such as mobile cations and oxygen vacancies. Additionally, both the magnitude and length scale of charge transfer between the bulk and surface layer will be investigated. The project will combine atomically precise materials synthesis with surface-sensitive element-specific spectroscopy and microscopy, considering the family of (001)-oriented perovskite oxides for the oxygen evolution reaction (OER). Together, these studies will build understanding and ultimately control of the dynamic evolution of material interfaces, coupled with their activity and stability in the OER, enabling materials design to exploit this interphase region through innovative assemblies of matter. The work in this proposal will further be incorporated into hands-on learning activities and open-ended projects centered around electrochemical devices for energy conversion and storage in undergraduate curriculum and outreach to underrepresented groups.The project is co-funded by the Catalysis program in the Chemical, Bioengineering, Environmental and Transport Processes (CBET) Division and the Chemical Catalysis program in the Chemistry Division.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.