Carrasco Jose A, Seijas-Da Silva Alvaro, Oestreicher Víctor, Romero Jorge, Márkus Bence G, Simon Ferenc, Vieira Bruno J C, Waerenborgh João C, Abellán Gonzalo, Coronado Eugenio
Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático José Beltrán 2, 46980, Paterna, Valencia, Spain.
Department of Physics, Budapest University of Technology and Economics, POBox 91, 1521 Budapest, Hungary and MTA-BME Lendület Spintronics Research Group (PROSPIN), 1521, Budapest, Hungary.
Chemistry. 2020 May 20;26(29):6504-6517. doi: 10.1002/chem.201905397. Epub 2020 Apr 6.
Layered double hydroxides (LDHs) are a class of 2D anionic materials exhibiting wide chemical versatility and promising applications in different fields, ranging from catalysis to energy storage and conversion. However, the covalent chemistry of this kind of 2D materials is still barely explored. Herein, the covalent functionalization with silanes of a magnetic NiFe-LDH is reported. The synthetic route consists of a topochemical approach followed by anion exchange reaction with surfactant molecules prior to covalent functionalization with the (3-aminopropyl)triethoxysilane (APTES) molecules. The functionalized NiFe-APTES was fully characterized by X-ray diffraction, infrared spectroscopy, electron microscopy, thermogravimetric analysis coupled with mass spectrometry and Si solid-state nuclear magnetic resonance, among others. The effect on the electronic properties of the functionalized LDH was investigated by a magnetic study in combination with Mössbauer spectroscopy. Moreover, the reversibility of the silane-functionalization at basic pH was demonstrated, and the quality of the resulting LDH was proven by studying the electrochemical performance in the oxygen evolution reaction in basic media. Furthermore, the anion exchange capability for the NiFe-APTES was tested employing Cr , resulting in an increase of 200 % of the anion retention. This report allows for a new degree of tunability of LDHs, opening the door to the synthesis of new hybrid architectures and materials.
层状双氢氧化物（LDHs）是一类二维阴离子材料，具有广泛的化学多样性，在从催化到能量存储与转换等不同领域有着广阔的应用前景。然而，这类二维材料的共价化学仍鲜有探索。在此，我们报道了磁性NiFe-LDH与硅烷的共价功能化。合成路线包括一种拓扑化学方法，随后在与（3-氨丙基）三乙氧基硅烷（APTES）分子进行共价功能化之前，与表面活性剂分子进行阴离子交换反应。通过X射线衍射、红外光谱、电子显微镜、热重分析结合质谱以及硅固态核磁共振等手段对功能化的NiFe-APTES进行了全面表征。通过磁性研究结合穆斯堡尔光谱研究了功能化LDH对电子性质的影响。此外，还证明了在碱性pH条件下硅烷功能化的可逆性，并通过研究碱性介质中析氧反应的电化学性能证明了所得LDH的质量。此外，使用Cr测试了NiFe-APTES的阴离子交换能力，结果阴离子保留率提高了200%。本报告为LDHs提供了新的可调谐度，为新型混合结构和材料的合成打开了大门。
