Muramatsu Keisuke, Kuroda Yoshiyuki, Wada Hiroaki, Shimojima Atsushi, Kuroda Kazuyuki
Department of Advanced Science and Engineering, Faculty of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan.
Graduate School of Engineering Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan.
Inorg Chem. 2021 May 17;60(10):7094-7100. doi: 10.1021/acs.inorgchem.0c03830. Epub 2021 May 3.
Various methods for the preparation of inorganic nanosheets have been established and they have contributed to the substantial development of the research on diverse two-dimensional materials. Covalent surface modification of layered metal hydroxides with alkoxy groups is known to effectively weaken the interactions between layers, although the modified ligands are irreversibly immobilized. This study proposes the use of methanol as a removable surface modifier forming monodentate alkoxy bonds to prepare nickel hydroxide nanosheets through hydrolysis. Methoxylated layered nickel hydroxide, consisting of randomly stacked nano-sized nickel hydroxide sheets (10-20 nm in size) having Ni-OCH groups on its surface, was synthesized in a powder form through the precipitation reaction of a nickel salt in methanol at room temperature. After dispersing the aggregated methoxylated nickel hydroxide in water, single-layer nickel hydroxide nanosheets with a thickness of 1.2 nm and a lateral size of 460 nm at maximum, which is larger than the size of original methoxylated nickel hydroxide were found in the suspension. The time-course experiments during hydrolysis suggested that two-dimensional crystal growth of exfoliated nickel hydroxide sheets proceeded, resulting in the formation of the nanosheets. Moreover, single-layer and nano-sized cobalt hydroxide was prepared through a similar manner. This work demonstrates that two-dimensional alkoxides consisting of polymeric M-O-M bonds are useful precursors for the design of metal-hydroxide-based nanomaterials.
已经建立了各种制备无机纳米片的方法，这些方法为多种二维材料的研究取得实质性进展做出了贡献。已知用烷氧基对层状金属氢氧化物进行共价表面改性可有效减弱层间相互作用，尽管改性配体是不可逆固定的。本研究提出使用甲醇作为可去除的表面改性剂，通过水解形成单齿烷氧基键来制备氢氧化镍纳米片。通过镍盐在甲醇中于室温下的沉淀反应，以粉末形式合成了甲氧基化层状氢氧化镍，其由表面带有Ni - OCH基团的随机堆叠的纳米尺寸氢氧化镍片（尺寸为10 - 20 nm）组成。将聚集的甲氧基化氢氧化镍分散在水中后，在悬浮液中发现了厚度为1.2 nm且横向尺寸最大为460 nm的单层氢氧化镍纳米片，其尺寸大于原始甲氧基化氢氧化镍的尺寸。水解过程中的时间进程实验表明，剥落的氢氧化镍片的二维晶体生长进行，从而形成了纳米片。此外，通过类似的方式制备了单层且纳米尺寸的氢氧化钴。这项工作表明，由聚合物M - O - M键组成的二维醇盐是设计金属氢氧化物基纳米材料的有用前体。
