Combined spectroscopy and microscopy of supported MoS2 nanoparticles
Résumé
Supported molybdenum-sulfide nanoparticles are known catalysts for petroleum hydrodesulfurization as well as for electrochemical hydrogen evolution. In this study, we investigate molybdenum-sulfide nanoparticles supported on Au(1 1 1) using X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM), aiming to correlate spectroscopically determined chemical states with atomically resolved nanostructure. The results of this study allow us to conclude the following: (1) the XPS results from our model system are in good agreement with previously published results on supported MoS2 for industrial applications, validating in part the fidelity of the model system; (2) STM reveals that catalytically active, crystalline MoS2 nanoparticles exhibiting the well-known metallic edge state are only present after a post-deposition annealing step in the synthesis procedure, without which the particles exhibit amorphous shapes and incomplete sulfidation; and (3) the sulfided nanoparticles are found to be stable in air at room temperature. © 2009 Elsevier B.V. All rights reserved.
Mots clés
Au(1 1 1)
Chemical state
Edge state
Hydrogen evolutions
Model systems
Nano structures
Post-deposition annealing
Room temperatures
Sulfidation
Supported nanoparticle
Synthesis procedures
Xps
Electron spectroscopy
Gold
Hydrodesulfurization
Hydrogen
Hydrogen sulfide
Industrial applications
Molybdenum
Molybdenum compounds
Nanoparticles
Photoelectricity
Photoionization
Photons
Scanning
Scanning tunneling microscopy
Spectrum analysis
X ray photoelectron spectroscopy