Dey Gaurav R, Soliman Samuel S, McCormick Connor R, Wood Charles H, Katzbaer Rowan R, Schaak Raymond E
Department of Chemistry, Department of Chemical Engineering, and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
ACS Nanosci Au. 2023 Nov 16;4(1):3-20. doi: 10.1021/acsnanoscienceau.3c00049. eCollection 2024 Feb 21.
Materials referred to as "high entropy" contain a large number of elements randomly distributed on the lattice sites of a crystalline solid, such that a high configurational entropy is presumed to contribute significantly to their formation and stability. High temperatures are typically required to achieve entropy stabilization, which can make it challenging to synthesize colloidal nanoparticles of high entropy materials. Nonetheless, strategies are emerging for the synthesis of colloidal high entropy nanoparticles, which are of interest for their synergistic properties and unique catalytic functions that arise from the large number of constituent elements and their interactions. In this Perspective, we highlight the classes of materials that have been made as colloidal high entropy nanoparticles as well as insights into the synthetic methods and the pathways by which they form. We then discuss the concept of "high entropy" within the context of colloidal materials synthesized at much lower temperatures than are typically required for entropy to drive their formation. Next, we identify and address challenges and opportunities in the field of high entropy nanoparticle synthesis. We emphasize aspects of materials characterization that are especially important to consider for nanoparticles of high entropy materials, including powder X-ray diffraction and elemental mapping with scanning transmission electron microscopy, which are among the most commonly used techniques in laboratory settings. Finally, we share perspectives on emerging opportunities and future directions involving colloidal nanoparticles of high entropy materials, with an emphasis on synthesis, characterization, and fundamental knowledge that is needed for anticipated advances in key application areas.
被称为“高熵”的材料包含大量随机分布在晶体固体晶格位点上的元素，因此假定高组态熵对它们的形成和稳定性有显著贡献。通常需要高温来实现熵稳定，这可能使得合成高熵材料的胶体纳米颗粒具有挑战性。尽管如此，合成胶体高熵纳米颗粒的策略正在出现，这些纳米颗粒因其大量组成元素及其相互作用所产生的协同性质和独特催化功能而备受关注。在这篇综述中，我们重点介绍了已制成胶体高熵纳米颗粒的材料类别，以及对合成方法及其形成途径的见解。然后，我们在比熵驱动其形成所需的典型温度低得多的温度下合成的胶体材料背景下讨论“高熵”的概念。接下来，我们识别并解决高熵纳米颗粒合成领域中的挑战和机遇。我们强调了对于高熵材料纳米颗粒而言特别重要的材料表征方面，包括粉末X射线衍射和扫描透射电子显微镜的元素映射，这些是实验室环境中最常用的技术之一。最后，我们分享了关于高熵材料胶体纳米颗粒的新兴机遇和未来方向的观点，重点是关键应用领域预期进展所需的合成、表征和基础知识。
