Metal Oxynitrides: Tuning Metal-N and Metal-O Interactions for Improved Electrocatalytic Properties at the Liquid/Solid Interface

氨的生产对农业至关重要，但目前的生产过程是能源密集型的，同时也会产生大量的二氧化碳。地球上丰富的过渡金属氧化物和氮氧化物是用作二氮合成氨的催化剂的主要材料，二氮占地球大气的78%。然而，由于对复杂电解质/固体界面上氮化氧表面化学的原子水平理解尚不清楚，这些材料在技术上的重要应用的广泛使用提出了重大挑战。该项目由材料研究部固态与材料化学和陶瓷项目资助，Cundari, D 'Souza和Kelber以及他们在北德克萨斯大学（UNT）的研究小组将研究通过更节能的途径将二氮转化为氨的基本化学相互作用。这些研究将有助于了解化学和材料因素，这些因素对于优化从二氮制氨的新材料以及应用于其他重要的工业反应是最重要的。参与的学生研究人员将学习广泛的实验和计算技能，pi将与UNT的其他教师和学生合作，用英语和西班牙语就重要的化学主题进行简短的演讲，以提高高中生对化学和其他STEM职业的兴趣。从氮气中生产NH3依赖于高温Haber-Bosch工艺，该工艺消耗大量能源并产生大量二氧化碳，新材料的设计提供了一种环保/能源友好的生产氮气的替代方案，可以对农业，节能和环境产生重大影响。地球上丰富的过渡金属氧化物和氮氧化物在能源和环境应用方面的兴趣正在迅速增长，但N， O和金属中心在N2还原中的基本作用尚未得到很好的理解。该项目由材料研究部固态与材料化学和陶瓷项目支持，将研究电解质/固体界面上与二氮还原为氨有关的基本相互作用，以及其他电催化过程，如氢和氧的形成。电化学方法，结合原位和operando表面科学探针，将探索控制催化效率和选择性的电解质/氮氧化物界面的基本相互作用。实验研究将得到理论努力的支持和指导，这些理论努力集中在n -支撑与o -支撑金属中心的反应途径的能量学上。学生将学习实验和理论方法，这将提高他们在学术和工业研究环境中的能力。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。

Non-technical SummaryAmmonia production is vital to agriculture but is currently produced by an energy-intensive process that also produces significant amounts of CO2. Earth-abundant transition metal oxides and oxynitrides are the primary materials used as catalysts for synthesis of ammonia from dinitrogen, which comprises 78% of Earth’s atmosphere. Widespread use of these materials for such technologically important applications poses a significant challenge, however, as the atomic-level understanding of oxynitride surface chemistry at the complex electrolyte/solid interface is not well understood. With this project, supported by the Solid State and Materials Chemistry and Ceramics programs in the Division of Materials Research, Profs. Cundari, D’Souza and Kelber and their research groups at the University of North Texas (UNT) will investigate fundamental chemical interactions relevant to the conversion of dinitrogen to ammonia via more energy-efficient routes. The studies will help in understanding the chemical and material factors that are most important for optimizing new materials for ammonia production from dinitrogen, and applications to other important industrial reactions. Involved student researchers will learn a wide range of experimental and computational skills and the PIs will collaborate with other UNT faculty and students to develop brief presentations – in English and Spanish – on important chemistry topics to heighten interest of high school students in pursing Chemistry and other STEM careers.Technical SummaryThe production of NH3 from N2 relies on the high temperature Haber-Bosch process which consumes much energy and produces significant CO2 and the design of new materials to provide an environmentally/energetically friendly alternative to produce N2 can have significant impact on agriculture, energy saving, and the environment. Earth-abundant transition metal oxides and oxynitrides are rapidly growing in interest for energy and environmental applications, but the fundamental roles of N, O and metal centers in N2 reduction are, however, not well understood. This project, supported by the Solid State and Materials Chemistry and Ceramics programs in the Division of Materials Research, will investigate fundamental interactions at the electrolyte/solid interface relevant to the reduction of dinitrogen to ammonia, and to other electrocatalytic processes, such as the formation of hydrogen and oxygen. Electrochemical methods, combined with in situ and operando surface science probes, will probe the fundamental interactions at the electrolyte/oxynitride interface governing both catalytic efficiency and selectivity. Experimental studies will be both supported and guided by theoretical efforts focused on the energetics of reaction pathways at N-supported vs. O-supported metal centers. Students involved will learn both experimental and theoretical methods, which will enhance their capabilities in both academic and industrial research environments.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.