fulltext.study @t Gmail

Location of Co and Ni promoter atoms in multi-layer MoS2 nanocrystals for hydrotreating catalysis

Paper ID Volume ID Publish Year Pages File Format Full-Text
53385 46966 2016 7 PDF Available
Title
Location of Co and Ni promoter atoms in multi-layer MoS2 nanocrystals for hydrotreating catalysis
Abstract

•Industrial-style hydrotreating catalysts are examined by STEM-EEL spectrum imaging.•Element maps resolve Co and Ni atoms at edges of multi-layer MoS2 nanocrystals.•The edge-located Co and Ni atoms are proposed to promote hydrotreating reactions differently.

The location of Co and Ni promoter atoms in industrial-style hydrotreating catalysts is examined by combining aberration-corrected scanning transmission electron microscopy and electron energy loss spectrum imaging. The observations unambiguously demonstrate that both Co and Ni promoter atoms occupy sites at all low-indexed edge terminations of hexagonally shaped multi-layer MoS2 nanocrystals. In contrast, similar observations for single-layer MoS2 nanocrystals show that Co-promoter atoms preferentially attach at the (−1 0 0) S-edge termination and are absent at the (1 0 0) Mo-edge termination. The apparent discrepancy between single- and multi-layer MoS2 nanocrystals can be explained by the 2H-MoS2 crystal structure, for which successive MoS2 layers alternatingly expose Mo- and S-edge terminations in any of the low-indexed directions. Thus, the multi-layer Co–Mo–S and Ni–Mo–S nanocrystals, formed in the present type of industrial-style hydrotreating catalyst, are consistently described as a superposition of single-layer Co–Mo–S and Ni–Mo–S structures, and in turn, provide promoted edge sites with different steric accessibility for the organic compounds in mineral oil distillates.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (277 K)Download as PowerPoint slide

Keywords
Heterogeneous catalysis; Hydrodesulfurization; Molybdenum disulfide; Scanning transmission electron microscopy; Electron energy loss spectroscopy
First Page Preview
Location of Co and Ni promoter atoms in multi-layer MoS2 nanocrystals for hydrotreating catalysis
Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 261, 1 March 2016, Pages 75–81
Authors
, , , , , , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis