Chemical Insights into High Entropy Alloy Nanoparticle Formation and Reactivity

在化学系大分子、超分子和纳米化学项目的支持下，宾夕法尼亚州立大学的Schaak教授将开发化学反应，形成高熵合金的纳米颗粒，这种合金含有五种或更多种元素。这些纳米颗粒中的大量元素可能导致在许多应用中有用的独特性质，包括作为与清洁能源技术相关的化学反应的催化剂。Schaak教授和他的团队将开发用于在溶液中制造高熵合金纳米颗粒的化学反应，并了解它们是如何，为什么以及何时形成的。他们还将定义这些纳米颗粒的化学反应性，以了解它们在暴露于不同试剂时如何转化。从这项研究中获得的知识将导致催化和其他领域的未来进展，通过控制纳米级特征，以新的方式调整高熵合金的性能。Schaak教授和他的团队将根据高熵合金纳米颗粒合成和表征的独特方面开发教程和学习模块，这将影响广泛的学生和研究人员社区。 Schaak教授还将为早期职业研究人员启动一个虚拟网络和指导计划。大多数合成高熵合金纳米颗粒的策略需要高温加热和快速冷却负载在耐火支撑物上的金属盐，这提供了纳米级的稳定性。然而，这些方法不允许更精细地控制众所周知会影响性质（包括尺寸、均匀性和形状）的纳米颗粒特征。在溶液中发生的化学反应非常适合于纳米颗粒的合成，但高熵合金的溶液路线仍然有限，并且对它们如何形成，生长和转化知之甚少。Schaak教授的研究团队将阐明选定的高熵合金纳米颗粒在溶液中形成的途径，并评估不同的反应参数如何影响反应结果。关于高熵合金纳米颗粒的化学反应性的知识也是有限的，这对于在应用中使用它们是重要的。高熵合金纳米颗粒中的大量组成元素可能导致独特的协同性能，例如改性的选择性和增加的催化稳定性。Schaak教授和他的团队将研究高熵合金纳米颗粒的反应性和稳定性，包括在各种无机试剂的溶液中。这些实验将导致形成新的高熵合金纳米粒子类别，并提供有关如何控制和调整胶体高熵合金纳米粒子的应用相关特性的基础知识。该奖项反映了NSF的法定使命，并已被认为值得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的支持。

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professor Schaak of Pennsylvania State University will develop chemical reactions to form nanoparticles of high entropy alloys, which contain five or more elements. The large number of elements in these nanoparticles may lead to unique properties that are useful in many applications, including as catalysts for chemical reactions relevant to clean energy technologies. Prof. Schaak and his group will develop chemical reactions for making high entropy alloy nanoparticles in solution and understand how, why, and when they form. They will also define the chemical reactivity of these nanoparticles to understand how they transform when exposed to different reagents. The knowledge gained from this research will lead to future advances in catalysis and other fields by allowing the properties of high entropy alloys to be tuned in new ways through control over nanoscopic features. Prof. Schaak and his group will develop tutorials and learning modules based on unique aspects of high entropy alloy nanoparticle synthesis and characterization, which will impact a broad community of students and researchers. Prof. Schaak will also launch a virtual networking and mentoring initiative for early-career researchers.Most strategies for synthesizing high entropy alloy nanoparticles require high-temperature heating and rapid cooling of metal salts loaded onto refractory supports, which provide nanoscale stabilization. However, these methods do not allow finer control over nanoparticle features that are well known to influence properties, including size, uniformity, and shape. Chemical reactions that occur in solution are well suited for nanoparticle synthesis, but solution routes to high entropy alloys remain limited, and little is known about how they form, grow, and transform. Prof. Schaak’s research team will elucidate the pathways by which selected high entropy alloy nanoparticles form in solution and evaluate how diverse reaction parameters influence reaction outcomes. There also is limited knowledge about the chemical reactivity of high entropy alloy nanoparticles, which is important for using them in applications. The large number of constituent elements in high entropy alloy nanoparticles is likely to lead to unique synergistic properties, such as modified selectivity and increased stability in catalysis. Prof. Schaak and his group will study the reactivity and stability of high entropy alloy nanoparticles, including in solution with a broad range of inorganic reagents. These experiments will lead to the formation of new classes of high entropy alloy nanoparticles and provide foundational knowledge about how application-relevant features of colloidal high entropy alloy nanoparticles can be controlled and tuned.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.