Achieving a molecular level understanding of chemical reactions on the surface of solid-state nanomaterials is important, but challenging. For example, the fully saturated basal plane is believed to be practically inert and its surface chemistry has been poorly explored, while two-dimensional (2D) layered transition-metal chalcogenides (TMCs) display unique reactivities due to their unusual anisotropic nature, where the edges consisting of unsaturated metals and chalcogens are sites for key chemical reactions. Herein, we report the use of Lewis acids/bases to elucidate the chemical reactivity of the basal plane in 2D layered TMCs. Electrophilic addition by Lewis acids (i.e., AlCl3) selectively onto sulfides in the basal plane followed by transmetalation and subsequent etching affords nanopores where such chemical activations are initiated and propagated from the localized positions of the basal plane. This new method of surface modification is generally applicable not only to various chemical compositions of TMCs, but also in crystal geometries such as 1T and 2H. Nanoporous NbS2 obtained by this method was found to have an enhanced electrochemical energy storage capacity, offering this chemical strategy to obtain functional 2D layered nanostructures.

中文翻译：

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二维过渡金属硫族化物纳米结构中基面的活化

实现对固态纳米材料表面化学反应的分子水平理解很重要，但具有挑战性。例如，完全饱和的基面被认为实际上是惰性的，其表面化学研究很少，而二维 (2D) 层状过渡金属硫属元素化物 (TMC) 由于其不寻常的各向异性性质而显示出独特的反应性，其中由不饱和金属和硫属元素组成的边缘是关键化学反应的场所。在此，我们报告了使用路易斯酸/碱来阐明二维分层 TMC 中基面的化学反应性。路易斯酸的亲电加成（即 AlCl3) 选择性地到基面中的硫化物上，然后进行金属转移和随后的蚀刻提供纳米孔，其中这种化学活化从基面的局部位置开始和传播。这种新的表面改性方法不仅适用于 TMC 的各种化学成分，还适用于 1T 和 2H 等晶体几何结构。发现通过这种方法获得的纳米多孔 NbS2 具有增强的电化学储能能力，为获得功能性二维层状纳米结构提供了这种化学策略。