Production of monolayer-rich gold-decorated 2H–WS2 nanosheets by defect engineering

• Published in: NPJ 2D materials and applications Vol. 1; no. 1
• Main Authors: Dunklin, Jeremy R., Lafargue, Paul, Higgins, Thomas M., Forcherio, Gregory T., Benamara, Mourad, McEvoy, Niall, Roper, D. Keith, Coleman, Jonathan N., Vaynzof, Yana, Backes, Claudia
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 08.01.2018
• Subjects: Catalytic activity; Decoration; Defects; Dispersions; Enrichment; Flakes (defects); Gold; Hydrogen evolution reactions; Liquid phases; Monolayers; Nanoparticles; Nanosheets; Nanostructure; Optical properties; Photoluminescence; Sheets; Transition metal compounds; Tungsten disulfide
• ISSN: 2397-7132; 2397-7132
• DOI: 10.1038/s41699-017-0045-z

Abstract 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 WS 2 undergoes a spontaneous redox reaction with AuCl 3 . We propose that thiol groups at edges and defects sites reduce the AuCl 3 to Au 0 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.