INFEWS N/P/H2O: SusChEM: Collaborative: Controlling Spatial Composition of Nonprecious Metal-based Heteronanostructures for Enhanced Electrocatalytic Performance

该项目涉及与从水和氮中生产氨（NH3）相关的催化电化学过程，以及分解水以产生用于储能、燃料和化学品生产的氢所需的析氧反应（OER）。这两种工艺都为依赖碳氢化合物资源获取所需氢气的传统工艺提供了替代方案。因此，该项目将支持国家科学基金会在可持续能源生产和食品、能源和水（infws）创新领域的倡议，后者通过NH3作为世界上氮基肥料生产的主要原料的重要性。特别是，该研究旨在为目标电化学过程发现高效的非贵金属纳米催化剂，这些催化剂可以在环境温度条件下运行，而不是碳氢化合物基技术所需的高温条件。电催化氮还原反应（NRR）产生NH3的净能耗低于传统的Haber-Bosch热催化过程，后者占世界能源消耗的1%至2%。具体而言，该项目寻求在NRR和OER催化电解槽方面取得进展。这项工作将专注于在碱性电化学环境中工作的非贵金属双金属催化剂，从而实现贵金属的低成本、技术支持替代品。该项目建立在初步数据的基础上，这些数据表明，对异质结构纳米颗粒的空间组成和形态的特定控制将增强催化活性，并建立对纳米颗粒形式的关键双金属系统的组成-活性关系的基本理解。具体的研究目标是：(1)合成和表征由杂核（含/不含合金壳）组成的非贵重Fe-Ni双金属的新型杂电结构；(2)评价电化学NRR和OER催化剂在碱性体系中的反应活性和选择性；(3)开发利用x射线吸收光谱将结构和组成与电催化活性联系起来的操作方法。除了目标反应之外，低成本、非贵重的纳米颗粒催化剂的引入对包括电催化在内的广泛催化应用越来越感兴趣。所提出的新型非贵重纳米结构的验证，其中特定的空间组成与性能指标和操作性表征相关，将使催化剂设计的方法能够广泛应用，使成本和性能具有竞争力的催化剂商业化。此外，通过结构设计控制催化剂选择性将使与水处理、能量转换和农业相关的重要反应取得关键进展。为了实现这一目标，将建立一种研究和教育的综合方法，以增加学生对STEM研究的参与，追求STEM专业，并培养纳米催化剂跨学科领域的下一代领导者。调查人员将积极招募学生，特别是未被代表的学生群体，参加他们的研究项目。研究结果将会整合到化学与化学工程系的本科与研究生课程的教学中。此外，研究人员将通过美国化学学会科学教练和阿肯色大学工程学院项目，让K-12教师参与目前的暑期项目，并为学生和K-12教师组织一次关于纳米催化剂发现的年度研讨会。

The project addresses catalytic electrochemical processes related to the production of ammonia (NH3) from water and nitrogen, and the oxygen evolution reaction (OER) needed to split water to produce hydrogen for energy storage and fuel and chemical production. Both processes offer alternatives to conventional processes that rely on hydrocarbon resources for the needed hydrogen. Thus the project will support NSF's initiatives in the areas of sustainable energy generation and Innovations at the Nexus of Food, Energy, and Water (INFEWS), the latter via the importance of NH3 as the world's primary raw material for nitrogen-based fertilizer production. In particular, the research is aimed at discovering efficient, nonprecious metal nanocatalysts for the targeted electrochemical processes that can operate at ambient temperature conditions rather than the high-temperature conditions required for hydrocarbon-based technologies. The electrocatalytic nitrogen reduction reaction (NRR) has the potential to generate NH3 at lower net energy consumption than the traditional Haber-Bosch thermal catalytic process which accounts for between 1 and 2% of world energy consumption. Specifically, the project seeks advances in catalytic electrolyzers for both NRR and OER. The work will focus exclusively on nonprecious metal bimetallic catalysts operating in alkaline electrochemical environments, thus enabling low-cost, technology-enabling alternatives to the precious metals. The project is built on preliminary data suggesting that specific control of the spatial composition and morphology of heterostructured nanoparticles will enable enhanced catalytic activity and also establish fundamental understanding of composition-activity relationships for key bimetallic systems in nanoparticle form. The specific research objectives are: (1) to synthesize and characterize novel heteronanostructures of nonprecious Fe-Ni bimetals composed of a hetero-core with/without an alloyed shell, (2) to evaluate the reactivity and selectivity of the catalysts for electrochemical NRR and OER in alkaline systems, and (3) to develop in operando methods to correlate the structure and composition with electrocatalytic activity using x-ray absorption spectroscopy. Beyond the targeted reactions, introduction of low-cost, nonprecious nanoparticle catalysts are of increasing interest for a broad range of catalytic applications, including electrocatalysis. Validation of the proposed novel nonprecious nanostructures, where specific spatial composition is correlated with the performance metrics and in operando characterization, will enable an approach to catalyst design that could be widely applied to enable cost- and performance-competitive catalysts for commercialization. Furthermore, controlling catalyst selectivity through structural design would enable key advances for important reactions related to water treatment, energy conversion, and agriculture. To support this objective, an integrated approach of research and education will be established to increase student participation in STEM research, to pursue STEM majors, and to train next-generation leaders in the interdisciplinary field of nanocatalysts. The investigators will actively recruit students, especially unrepresented student groups, to their research programs. The research findings will be integrated into teaching for undergraduate and graduate curriculum development in both Chemistry and Chemical Engineering departments. In addition, the investigators will strengthen the current summer programs by involving K-12 teachers through American Chemical Society Science Coaches and the University of Arkansas Engineering Academy Programs, as well as organizing an annual workshop for students and K-12 teachers on Nanocatalyst Discovery.