Characterization and thiophene hydrodesulfurization activity of amorphous-silica-alumina-supported NiW catalysts

Y. Meer, van der, E.J.M. Hensen, J.A.R. Veen, van, A.M. Kraan, van der

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

The influence of the preparation method and sulfidation conditions on the structure and activity of ASA-supported NiW catalysts was investigated by a combination of 57Co Mössbauer emission spectroscopy (MES), transmission electron microscopy (TEM), X-ray absorption spectroscopy (XAS), and thiophene hydrodesulfurization (HDS) activity measurements. Ni is sulfided already at low temperatures. This nickel sulfide phase redisperses at higher temperatures over the edges of WS2 particles to form "NiWS"-type phases. The formation of such highly active phases is facilitated by the partial transformation of intermediate WOxSy phases to WS2 (W LIII edge XAS) at 673 K. In addition to this "CoMoS" analogue nickel sulfide particles are present in dispersed form close to an oxysulfidic tungsten phase. It is found that the sulfidation of NiW/ASA closely resembles that of NiW/Al2O3. Trends in the HDS activity as a function of catalyst pretreatment were evaluated. A higher calcination temperature (from 673 to 823 K) decreases the HDS performance stemming from a lower W sulfidation degree and a more dominant presence of small oxysulfidic tungsten particles. Increasing the sulfidation pressure from atmospheric pressure to 15 bar leads to a strong increase of the HDS activity. Whereas sulfidation at 923 K results in a well-crystallized WS2 phase (XAS), the concomitant loss in dispersion (TEM) is detrimental to its performance. Moreover, indications are found that more complete crystallization of the WS2 phase results in a lower activity.
Original languageEnglish
Pages (from-to)433-446
Number of pages14
JournalJournal of Catalysis
Volume228
Issue number2
DOIs
Publication statusPublished - 2004

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sulfidation
Thiophenes
Hydrodesulfurization
Aluminum Oxide
Thiophene
thiophenes
Catalyst supports
Silicon Dioxide
X ray absorption spectroscopy
Alumina
aluminum oxides
Silica
silicon dioxide
catalysts
Tungsten
acetylsalicylic acid
absorption spectroscopy
Nickel
sulfides
Transmission electron microscopy

Cite this

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title = "Characterization and thiophene hydrodesulfurization activity of amorphous-silica-alumina-supported NiW catalysts",
abstract = "The influence of the preparation method and sulfidation conditions on the structure and activity of ASA-supported NiW catalysts was investigated by a combination of 57Co M{\"o}ssbauer emission spectroscopy (MES), transmission electron microscopy (TEM), X-ray absorption spectroscopy (XAS), and thiophene hydrodesulfurization (HDS) activity measurements. Ni is sulfided already at low temperatures. This nickel sulfide phase redisperses at higher temperatures over the edges of WS2 particles to form {"}NiWS{"}-type phases. The formation of such highly active phases is facilitated by the partial transformation of intermediate WOxSy phases to WS2 (W LIII edge XAS) at 673 K. In addition to this {"}CoMoS{"} analogue nickel sulfide particles are present in dispersed form close to an oxysulfidic tungsten phase. It is found that the sulfidation of NiW/ASA closely resembles that of NiW/Al2O3. Trends in the HDS activity as a function of catalyst pretreatment were evaluated. A higher calcination temperature (from 673 to 823 K) decreases the HDS performance stemming from a lower W sulfidation degree and a more dominant presence of small oxysulfidic tungsten particles. Increasing the sulfidation pressure from atmospheric pressure to 15 bar leads to a strong increase of the HDS activity. Whereas sulfidation at 923 K results in a well-crystallized WS2 phase (XAS), the concomitant loss in dispersion (TEM) is detrimental to its performance. Moreover, indications are found that more complete crystallization of the WS2 phase results in a lower activity.",
author = "{Meer, van der}, Y. and E.J.M. Hensen and {Veen, van}, J.A.R. and {Kraan, van der}, A.M.",
year = "2004",
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language = "English",
volume = "228",
pages = "433--446",
journal = "Journal of Catalysis",
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Characterization and thiophene hydrodesulfurization activity of amorphous-silica-alumina-supported NiW catalysts. / Meer, van der, Y.; Hensen, E.J.M.; Veen, van, J.A.R.; Kraan, van der, A.M.

In: Journal of Catalysis, Vol. 228, No. 2, 2004, p. 433-446.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Characterization and thiophene hydrodesulfurization activity of amorphous-silica-alumina-supported NiW catalysts

AU - Meer, van der, Y.

AU - Hensen, E.J.M.

AU - Veen, van, J.A.R.

AU - Kraan, van der, A.M.

PY - 2004

Y1 - 2004

N2 - The influence of the preparation method and sulfidation conditions on the structure and activity of ASA-supported NiW catalysts was investigated by a combination of 57Co Mössbauer emission spectroscopy (MES), transmission electron microscopy (TEM), X-ray absorption spectroscopy (XAS), and thiophene hydrodesulfurization (HDS) activity measurements. Ni is sulfided already at low temperatures. This nickel sulfide phase redisperses at higher temperatures over the edges of WS2 particles to form "NiWS"-type phases. The formation of such highly active phases is facilitated by the partial transformation of intermediate WOxSy phases to WS2 (W LIII edge XAS) at 673 K. In addition to this "CoMoS" analogue nickel sulfide particles are present in dispersed form close to an oxysulfidic tungsten phase. It is found that the sulfidation of NiW/ASA closely resembles that of NiW/Al2O3. Trends in the HDS activity as a function of catalyst pretreatment were evaluated. A higher calcination temperature (from 673 to 823 K) decreases the HDS performance stemming from a lower W sulfidation degree and a more dominant presence of small oxysulfidic tungsten particles. Increasing the sulfidation pressure from atmospheric pressure to 15 bar leads to a strong increase of the HDS activity. Whereas sulfidation at 923 K results in a well-crystallized WS2 phase (XAS), the concomitant loss in dispersion (TEM) is detrimental to its performance. Moreover, indications are found that more complete crystallization of the WS2 phase results in a lower activity.

AB - The influence of the preparation method and sulfidation conditions on the structure and activity of ASA-supported NiW catalysts was investigated by a combination of 57Co Mössbauer emission spectroscopy (MES), transmission electron microscopy (TEM), X-ray absorption spectroscopy (XAS), and thiophene hydrodesulfurization (HDS) activity measurements. Ni is sulfided already at low temperatures. This nickel sulfide phase redisperses at higher temperatures over the edges of WS2 particles to form "NiWS"-type phases. The formation of such highly active phases is facilitated by the partial transformation of intermediate WOxSy phases to WS2 (W LIII edge XAS) at 673 K. In addition to this "CoMoS" analogue nickel sulfide particles are present in dispersed form close to an oxysulfidic tungsten phase. It is found that the sulfidation of NiW/ASA closely resembles that of NiW/Al2O3. Trends in the HDS activity as a function of catalyst pretreatment were evaluated. A higher calcination temperature (from 673 to 823 K) decreases the HDS performance stemming from a lower W sulfidation degree and a more dominant presence of small oxysulfidic tungsten particles. Increasing the sulfidation pressure from atmospheric pressure to 15 bar leads to a strong increase of the HDS activity. Whereas sulfidation at 923 K results in a well-crystallized WS2 phase (XAS), the concomitant loss in dispersion (TEM) is detrimental to its performance. Moreover, indications are found that more complete crystallization of the WS2 phase results in a lower activity.

U2 - 10.1016/j.jcat.2004.09.019

DO - 10.1016/j.jcat.2004.09.019

M3 - Article

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EP - 446

JO - Journal of Catalysis

JF - Journal of Catalysis

SN - 0021-9517

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ER -