Exploring the electron density localization in MoS2 nanoparticles using a localized-electron detector: Unraveling the origin of the one-dimensional metallic sites on MoS2 catalysts

The nature of the electron density localization in two MoS2 nanoclusters containing eight rows of Mo atoms, one with 100% sulphur coverage at the Mo edges (n8-100S) and the other with 50% coverage (n8-50S) was studied using a localized-electron detector function defined in the local moment representation. For n8-100S, pairs of neighboring S2 dimers cover the edges and the electron density localization function analysis shows the presence of a local triangular-shaped ring zone of highly delocalized electrons along these edges, which corresponds to a good metallic conductor zone. The optimized geometry analysis shows that the Mo-S2 bond length is much longer than that of the Mo-S bonds inside the cluster. The removal of one S atom from each sulphur dimer to create a cluster with 50% coverage produces a general compressive stress on the cluster optimized geometry, which shortens the Mo-S bond length, particularly at the edge. The electron density location function analysis shows that close to the cluster corners, a zone of highly delocalized electron zones with a characteristic semiconductor pattern and broken one-dimensional metallic ring was generated. These results suggest that the Mo-S2 bond elongation produced by the sulphur dimers is similar to a MoS2 monolayer under tensile strain and is the origin of the one-dimensional metallic sites at the Mo-edges. In general, the present findings show excellent agreement with the key features of the reported ambient pressure X-ray photoemission spectra and the corresponding simulated scanning tunneling microscopy images.

• Autores: Aray, Yosslen; Barrios, Antonio Díaz
• Tipo de recurso: Article of journal
• Fecha de publicación: 2018
• Institución: Universidad de Ciencias Aplicadas y Ambientales U.D.C.A
• Repositorio: Repositorio Institucional UDCA
• Idioma: eng
• OAI Identifier: oai:repository.udca.edu.co:11158/2334
• Acceso en línea: https://www.scopus.com/search/form.uri?display=basic
• Palabra clave: Electrones; Nanopartículas; Moléculas; Metales de transición; Molybdenum sulfide nanoclusters; One-dimensional metallic ring; Localized electron detector; Quantum theory of atoms in molecules
• Rights: openAccess
• License: Derechos Reservados - Universidad de Ciencias Aplicadas y Ambientales