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In-situ NAP-XPS reveals water-induced phase segregation of MoS2 nanoparticles in hydrodeoxygenation catalysis

Hedevang, Martin ; Mohrhusen, Lars ; Hallböök, Filip LU orcid ; Gajdek, Dorotea ; Merte, Lindsay R. ; Blomberg, Sara LU and Lauritsen, Jeppe V. (2026) In Journal of Catalysis 455.
Abstract

Hydrodeoxygenation (HDO) is a catalytic process applied for the reduction of oxygen levels in hydrocarbons from bio-derived feedstock as part of the processing into renewable fuel. The MoS2-based hydrotreating catalysts, currently being applied for the HDO reaction, are exposed to a complex environment consisting of O-rich hydrocarbons and water, which adversely impacts the state and stability of the catalyst. Here, we analyze the structural and chemical state changes of MoS2 in HDO-relevant conditions using a combination of surface-sensitive techniques applied to a planar model system consisting of supported and structurally well-defined single-layer MoS2 nanoparticles supported on Au(111). As observed... (More)

Hydrodeoxygenation (HDO) is a catalytic process applied for the reduction of oxygen levels in hydrocarbons from bio-derived feedstock as part of the processing into renewable fuel. The MoS2-based hydrotreating catalysts, currently being applied for the HDO reaction, are exposed to a complex environment consisting of O-rich hydrocarbons and water, which adversely impacts the state and stability of the catalyst. Here, we analyze the structural and chemical state changes of MoS2 in HDO-relevant conditions using a combination of surface-sensitive techniques applied to a planar model system consisting of supported and structurally well-defined single-layer MoS2 nanoparticles supported on Au(111). As observed by scanning tunnelling microscopy and near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS), the exposure to mbar pressure of H2O at 600 K induces clear changes in both the shape and size of the MoS2 nanoparticles, explained by a preferential oxidation and etching of MoS2 edges. MoOx is observed on the surface due to the spatial separation of the oxide and etched sulfide phase. Interestingly, when H2/H2O gas mixtures are applied, the sulfur reduction and oxidation of MoS2 appear to be decoupled, indicating that the removal of edge S species is not a prerequisite for oxidation. Furthermore, the formed MoOx showed a preferred reduction of the oxide over the sulfide. Importantly, the atom-resolved imaging reveals that the progressive etching and phase segregation of MoS2 maintains access to pristine edge sites of the single-layer MoS2, explaining why HDO activity can be maintained even for highly oxidized catalysts.

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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Bio-oil, Catalyst poisoning, Catalyst stability, Hydrodeoxygenation (HDO), Molybdenum sulfide (MoS), Near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS)
in
Journal of Catalysis
volume
455
article number
116705
publisher
Elsevier
external identifiers
  • scopus:105028628458
ISSN
0021-9517
DOI
10.1016/j.jcat.2026.116705
language
English
LU publication?
yes
id
f6fc50eb-866a-4c89-856a-d18199ca9cb6
date added to LUP
2026-02-18 12:36:36
date last changed
2026-02-18 12:37:20
@article{f6fc50eb-866a-4c89-856a-d18199ca9cb6,
  abstract     = {{<p>Hydrodeoxygenation (HDO) is a catalytic process applied for the reduction of oxygen levels in hydrocarbons from bio-derived feedstock as part of the processing into renewable fuel. The MoS<sub>2</sub>-based hydrotreating catalysts, currently being applied for the HDO reaction, are exposed to a complex environment consisting of O-rich hydrocarbons and water, which adversely impacts the state and stability of the catalyst. Here, we analyze the structural and chemical state changes of MoS<sub>2</sub> in HDO-relevant conditions using a combination of surface-sensitive techniques applied to a planar model system consisting of supported and structurally well-defined single-layer MoS<sub>2</sub> nanoparticles supported on Au(111). As observed by scanning tunnelling microscopy and near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS), the exposure to mbar pressure of H<sub>2</sub>O at 600 K induces clear changes in both the shape and size of the MoS<sub>2</sub> nanoparticles, explained by a preferential oxidation and etching of MoS<sub>2</sub> edges. MoO<sub>x</sub> is observed on the surface due to the spatial separation of the oxide and etched sulfide phase. Interestingly, when H<sub>2</sub>/H<sub>2</sub>O gas mixtures are applied, the sulfur reduction and oxidation of MoS<sub>2</sub> appear to be decoupled, indicating that the removal of edge S species is not a prerequisite for oxidation. Furthermore, the formed MoO<sub>x</sub> showed a preferred reduction of the oxide over the sulfide. Importantly, the atom-resolved imaging reveals that the progressive etching and phase segregation of MoS<sub>2</sub> maintains access to pristine edge sites of the single-layer MoS<sub>2</sub>, explaining why HDO activity can be maintained even for highly oxidized catalysts.</p>}},
  author       = {{Hedevang, Martin and Mohrhusen, Lars and Hallböök, Filip and Gajdek, Dorotea and Merte, Lindsay R. and Blomberg, Sara and Lauritsen, Jeppe V.}},
  issn         = {{0021-9517}},
  keywords     = {{Bio-oil; Catalyst poisoning; Catalyst stability; Hydrodeoxygenation (HDO); Molybdenum sulfide (MoS); Near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS)}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Journal of Catalysis}},
  title        = {{In-situ NAP-XPS reveals water-induced phase segregation of MoS<sub>2</sub> nanoparticles in hydrodeoxygenation catalysis}},
  url          = {{http://dx.doi.org/10.1016/j.jcat.2026.116705}},
  doi          = {{10.1016/j.jcat.2026.116705}},
  volume       = {{455}},
  year         = {{2026}},
}