Chemical functionalization of low-dimensional nanostructures has evolved as powerful tool to tailor the materials’ properties on demand. For two-dimensional transition metal dichalcogenides, functionalization strategies are mostly limited to the metallic 1T-polytype with only few examples showing a successful derivatization of the semiconducting 2H-polytype. Here, we describe that liquid-exfoliated WS₂ undergoes a spontaneous redox reaction with AuCl₃. We propose that thiol groups at edges and defects sites reduce the AuCl₃ to Au⁰ and are in turn oxidized to disulfides. As a result of the reaction, Au nanoparticles nucleate predominantly at edges with tuneable nanoparticle size and density. The drastic changes in nanosheet mass obtained after high loading with Au nanoparticles can be exploited to enrich the dispersions in laterally large, monolayered nanosheets by simple centrifugation. The optical properties (for example photoluminescence) of the monolayers remain pristine, while the electrocatalytic activity towards the hydrogen evolution reaction is significantly improved.

低维纳米结构的化学功能化已发展成为强大的工具，可根据需要调整材料的性能。对于二维过渡金属二卤化物，官能化策略主要限于金属1T多型，只有很少的例子显示了半导体2H多型的成功衍生化。在这里，我们描述了液体剥落的WS ₂与AuCl ₃发生自发的氧化还原反应。我们建议边缘和缺陷部位的硫醇基团将AuCl ₃还原为Au ⁰然后被氧化成二硫化物。作为反应的结果，Au纳米颗粒主要在具有可调节的纳米颗粒尺寸和密度的边缘成核。通过简单的离心，可以利用高负载金纳米颗粒后获得的纳米片质量的剧烈变化，以富集横向较大的单层纳米片中的分散体。单层的光学性质（例如光致发光）保持原始状态，而对氢析出反应的电催化活性得到显着改善。