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气中生产氨(NH3)相关的催化电化学过程，以及分解水以生产用于能量存储、燃料和化学生产的氢气所需的放氧反应(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NSF在食品、能源和水的纽带(INFEWS)可持续能源生产和创新领域的倡议，后者通过NH3作为世界氮基肥料生产的主要原材料的重要性而得到支持。特别是，这项研究的目的是发现有效的、非贵金属纳米催化剂，用于目标电化学过程，可以在常温条件下运行，而不是碳氢化合物技术所需的高温条件下运行。与占世界能源消耗1%至2%的传统Haber-Bosch热催化工艺相比，电催化氮气还原反应(NRR)具有以更低的净能耗产生NH3的潜力。具体地说，该项目寻求在用于NRR和OER的催化电解槽方面取得进展。这项工作将专门关注在碱性电化学环境中运行的非贵金属双金属催化剂，从而实现低成本、技术可行的贵金属替代品。该项目是建立在初步数据的基础上的，这些数据表明，对异质纳米颗粒的空间组成和形态的具体控制将能够增强催化活性，并建立对纳米颗粒形式的关键双金属体系的组成-活性关系的基本理解。具体的研究目标是：(1)合成和表征由带/不带合金化壳层的杂核组成的非贵金属Fe-Ni双金属的新型杂多酸结构；(2)在碱性体系中评价用于电化学NRR和OER的催化剂的反应活性和选择性；(3)发展用X-射线吸收光谱将结构和组成与电催化活性关联起来的方法。除了靶向反应外，低成本、非贵重的纳米催化剂的引入在包括电催化在内的广泛催化应用中越来越引起人们的兴趣。对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纵链表征相关，将使催化剂设计方法能够被广泛应用，从而使具有成本和性能竞争力的催化剂能够商业化。此外，通过结构设计控制催化剂的选择性将使与水处理、能源转换和农业相关的重要反应取得关键进展。为了支持这一目标，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，攻读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，特别是没有代表性的学生团体，加入他们的研究项目。研究成果将被整合到化学和化学工程系的本科生和研究生课程开发的教学中。此外，调查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教师参与到当前的暑期项目中来，并为学生和K-12教师组织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.