Lim Yongjun, Han Jae Hyo, Cheon Jinwoo
Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea.
Acc Chem Res. 2021 Apr 6;54(7):1565-1574. doi: 10.1021/acs.accounts.0c00802. Epub 2021 Mar 2.
ConspectusInorganic nanocrystal design has been continuously evolving with a better understanding of the chemical reaction mechanisms between chemical stimuli and nanocrystals. Under certain conditions, molecular compounds can be effective as chemical stimuli to induce transformative reactions of nanocrystals toward new materials that would differ in geometric shape, composition, and crystallographic structure. To explore such evolutionary processes, two-dimensional (2D) layered transition-metal chalcogenide (TMC) nanostructures are an interesting structural platform because they not only exhibit unique transformation pathways due to their structural anisotropy but also present new opportunities for improved material properties for potential applications such as catalysis and energy conversion and storage. The high surface area/volume ratio, interlayer van der Waals (vdW) spacing, and different coordination states between the unsaturated edges and the fully saturated basal planes of the chalcogens are characteristic of 2D layered TMC nanostructures, which subsequently lead to anisotropic chemical processes during chemical transformations, such as regioselective reactions at the interfacial boundaries in the pathways for either porous or solid heteronanostructures. In this Account, we first discuss the chemical reactivity of 2D layered TMC nanostructures. By categorizing the external stimuli in terms of chemical principles, such as Lewis acid-base chemistry, a desirable regioselective chemical reaction can occur with controlled reactivity. In association with the knowledge obtained from the nanoscale chemical reactivity of 2D layered nanocrystals, similar efforts in other important morphologies such as 1D and isotropic 0D nanocrystals are introduced. For instance, for 1D and 0D metal oxide nanocrystals, the effects of molecular stimuli on the atomic-level changes in the crystal lattice are demonstrated, eventually leading to a variety of shape transformations.
概述
随着对化学刺激与纳米晶体之间化学反应机制的深入理解，无机纳米晶体设计不断发展。在某些条件下，分子化合物可作为有效的化学刺激物，诱导纳米晶体向几何形状、组成和晶体结构不同的新材料发生转变反应。为探索此类演化过程，二维（2D）层状过渡金属硫族化合物（TMC）纳米结构是一个有趣的结构平台，因为它们不仅因其结构各向异性而展现出独特的转变途径，还为改善材料性能带来新机遇，可用于催化、能量转换与存储等潜在应用。二维层状TMC纳米结构具有高的表面积/体积比、层间范德华（vdW）间距，以及硫族元素不饱和边缘与完全饱和基面之间不同的配位状态，这些特性随后在化学转变过程中导致各向异性化学过程，例如在多孔或固体异质纳米结构途径中的界面边界处发生区域选择性反应。在本综述中，我们首先讨论二维层状TMC纳米结构的化学反应性。通过根据化学原理（如路易斯酸碱化学）对外部刺激进行分类，可发生具有可控反应性的理想区域选择性化学反应。结合从二维层状纳米晶体的纳米级化学反应获得的知识，还介绍了在其他重要形态（如一维和各向同性零维纳米晶体）方面的类似研究。例如，对于一维和零维金属氧化物纳米晶体，展示了分子刺激对晶格中原子水平变化的影响，最终导致多种形状转变。
