Extended Solid-Solubility Limit in Layered Double Hydroxides: Tuning the Anion-Adsorption Selectivity
Extended Solid-Solubility Limit in Layered Double Hydroxides: Tuning the Anion-Adsorption Selectivity
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DOI：
10.1021/acs.chemmater.2c02829
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发表时间：
2022-11
影响因子：
8.6
通讯作者：
Tomohito Sudare;Kenta Kawaguchi;Kazuse Yamaguchi;K. Hirono;Mongkol Tipplook;Hideki Tanaka;Fumitaka Hayashi;Katsuya Teshima
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文献类型：
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作者：
Tomohito Sudare;Kenta Kawaguchi;Kazuse Yamaguchi;K. Hirono;Mongkol Tipplook;Hideki Tanaka;Fumitaka Hayashi;Katsuya Teshima
含有热力学不混溶元素的非热力学固溶体中独特的原子排列有助于在各种材料中引入新的功能，如合金、陶瓷和配位聚合物。虽然高温猝灭法已被广泛应用于利用表面效应和高组态熵合成这类材料，但它不适用于高温下不稳定且只含有少量组分的材料。因此，需要一种新的合成策略。在这项研究中，我们证明了低温的拓扑化学反应促进了层状双氢氧化物(LDHs)的传统固溶度极限的扩展，LDHs是一类天然和合成的片状化合物。使用纯净的层状氧化物Na[Ni1-xFex]O2(0<；x<；1.0)，LDHs([Ni2+1-xFe3+x(OH)2]Cl-x·mH2O)的固溶度极限可以从x=0.33扩展到0.59。此外，与LDHs(x=0.30)相比，所得LDHs(x=0.59)对氟离子的选择性比对硫酸盐离子的选择性高20倍。这种选择性可能源于LDH氢氧化层中Fe3+-Fe3+相邻的三价阳离子的聚集，这导致了层间空间中硫酸盐和氯离子之间的空间位阻，同时阻止了氟离子和氯离子之间的阻碍。我们期望这项研究将指导未探索的非热力学固溶体的设计。
Unique atomic arrangements in nonthermodynamic solid solutions containing thermodynamically immiscible elements facilitate the introduction of new functionalities in various classes of materials, such as alloys, ceramics, and coordination polymers. Although high-temperature quenching has been widely used for synthesizing such materials with the aid of the surface effect and high configuration entropy, it is not applicable to materials that are unstable at high temperatures and contain only a few constituents. Thus, a new synthesis strategy is required. In this study, we demonstrated that a low-temperature topochemical reaction facilitates the extension of the conventional solid-solubility limit in layered double hydroxides (LDHs), a class of natural and synthetic lamellar compounds. Using a pristine layered oxide, Na[Ni1–xFex]O2(0 <x< 1.0), the solid-solubility limit of LDHs ([Ni2+1–xFe3+x(OH)2]Cl–x·mH2O) could be extended fromx= 0.33 to 0.59. Furthermore, compared to LDHs (x= 0.30), the obtained LDHs (x= 0.59) exhibited a 20-fold higher selectivity for fluoride ions than for sulfate ions. This selectivity possibly originated from a trivalent-cation clustering of Fe3+–Fe3+neighbors in the LDH hydroxide layers; this caused a steric hindrance between sulfate and chloride ions in the interlayer space while preventing hindrance between fluoride and chloride ions. We expect that this study will guide the design of unexplored nonthermodynamic solid solutions.