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Title: Monolayer-enriched production of Au-decorated WS 2 Nanosheets via Defect Engineering

Layered transition metal dichalcogenides (TMDs) represent a diverse, emerging source of two-dimensional (2D) nanostructures with broad application in optoelectronics and energy. Chemical functionalization has evolved into a powerful tool to tailor properties of these 2D TMDs; however, functionalization strategies have been largely limited to the metallic 1T-polytype. The work herein illustrates that 2H-semiconducting liquid-exfoliated tungsten disulfide (WS 2) undergoes a spontaneous redox reaction with gold (III) chloride (AuCl 3). Au nanoparticles (NPs) predominantly nucleate at nanosheet edges with tuneable NP size and density. AuCl 3 is preferentially reduced on multi-layer WS 2 and resulting large Au aggregates are easily separated from the colloidal dispersion by simple centrifugation. This process may be exploited to enrich the dispersions in laterally large, monolayer nanosheets. It is proposed that thiol groups at edges and defects sides reduce the AuCl 3 to Au 0 and are in turn oxidized to disulfides. Optical emission, i.e. photoluminescence, of the monolayers remained pristine, while the electrocatalytic activity towards the hydrogen evolution reaction is significantly improved. Taken together, these improvements in functionalization, fabrication, and catalytic activity represent an important advance in the study of these emerging 2D nanostructures.
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [5] ;  [4] ;  [5] ;  [2] ;  [2]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Ruprecht-Karls Univ. Heidelberg (Germany)
  3. Army Research Lab., Adelphi, MD (United States)
  4. Univ. of Arkansas, Fayetteville, AR (United States)
  5. Trinity College, Dublin (Ireland)
Publication Date:
Report Number(s):
Journal ID: ISSN 2059-8521; applab
Grant/Contract Number:
Accepted Manuscript
Journal Name:
MRS Advances
Additional Journal Information:
Journal Name: MRS Advances; Journal ID: ISSN 2059-8521
Materials Research Society (MRS)
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; self-assembly; functional; nanostructure
OSTI Identifier: