Unraveling the Redox Behavior of a CoMoS Hydrodesulfurization Catalyst: A Scanning Transmission X-ray Microscopy Study in the Tender X-ray Range

Journal article (2015)

Authors

M Al Samarai External organisation
F Meirer External organisation
C Karunakaran External organisation
J. Wang External organisation
Eelco T.C. Vogt External organisation
H.W. Zandbergen QN/High Resolution Electron Microscopy
T Weber External organisation
BM Weckhuysen External organisation
FMF de Groot External organisation
Research Group
QN/High Resolution Electron Microscopy
More Info
expand_more

Published Date

2015

Language

Undefined/Unknown

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Research Group

QN/High Resolution Electron Microscopy

Abstract

We visualize the elemental zoning in an alumina-supported cobalt molybdenum sulfide (CoMoS) catalyst with scanning transmission X-ray microscopy (STXM). We use the Canadian Light Source beamline 10-IDs (SM) unique combination of soft X-ray and tender X-ray STXM to determine the spatial variation of Co, Al, Mo, and S species. The results clearly show the correlation between cobalt and molybdenum and the anticorrelation between cobalt and alumina, confirming that Co is closely associated with the MoS2 phase. The tender X-ray STXM images show that the fresh catalyst particle contains a 50 nm ring of molybdenum oxide encapsulating the supported MoS2 phase. After the reduction at 200 degrees C with H-2, this oxide rim disappears and a uniform MoS2 distribution is found. Upon oxidation at 400 degrees C, the sulfur disappears from the catalyst sample and molybdenum is oxidized from a MoIV sulfide to a mainly tetrahedral MoVI oxide, while cobalt keeps its divalent nature and changes from a CoII sulfide to a CoII oxide.