Laboratory for High Performance Ceramics, Empa. Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH - 8600 Dübendorf, Switzerland.
Department of Applied Science and Technology, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy.
Inorg Chem. 2023 Mar 27;62(12):4999-5007. doi: 10.1021/acs.inorgchem.3c00179. Epub 2023 Mar 12.
High-entropy hydroxides are an emerging subcategory of high-entropy materials (HEMs), not only because they can serve as tailorable precursors to high-entropy oxides (HEOs) but also because they can have unique high-entropy properties themselves. Many hydroxide crystal structures that are important for various applications are yet to be studied within the context of high-entropy materials, and it is unknown if they can take a high-entropy form (typically five or more incorporated cations). One such material is the dawsonite-type structure, which is a material with applications in both catalysis and ceramics. This work focuses on the adaptation of a dawsonite-type structure (NHM(OH)CO) into a high-entropy material. Through a coprecipitation synthesis method, dawsonite-type materials readily took a high-entropy form with five cations that were equimolar and homogeneously distributed. The specific chemistries investigated were Al, Cr, Fe, and Ga with a fifth cation that was varied with increasing ionic radius (In, Er, Ho, Y, Eu, Ce, La). High-entropy dawsonites also exhibit the ″memory effects″ of non-high-entropy dawsonites. This work extends the field of high-entropy materials to include a structure that can serve as a material platform for the synthesis of high-entropy catalytic materials and ceramic powders.
高熵氢氧化物是高熵材料（HEMs）的一个新兴亚类，不仅因为它们可以作为高熵氧化物（HEOs）的可定制前体，还因为它们本身可以具有独特的高熵性质。许多对于各种应用很重要的氢氧化物晶体结构在高熵材料的背景下尚未得到研究，并且尚不清楚它们是否可以采用高熵形式（通常为五种或更多种掺入的阳离子）。这样的一种材料就是水羟硅铍石型结构，它在催化和陶瓷领域都有应用。这项工作主要集中在将水羟硅铍石型结构（NHM(OH)CO）改编为高熵材料。通过共沉淀合成方法，水羟硅铍石型材料很容易采用等摩尔且均匀分布的五种阳离子的高熵形式。所研究的具体化学物质是 Al、Cr、Fe 和 Ga，第五种阳离子则随着离子半径的增加而变化（In、Er、Ho、Y、Eu、Ce、La）。高熵水羟硅铍石也表现出非高熵水羟硅铍石的“记忆效应”。这项工作将高熵材料领域扩展到包括一种可以用作高熵催化材料和陶瓷粉末合成的材料平台的结构。
