An EXAFS Study on the Ni and W Environment in Carbon-Supported, Sulfided W and Ni-W Catalysts

Louwers, S.P.A.; Prins, R.

doi:10.1006/jcat.1993.1046

Cited by 70 publications

(26 citation statements)

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“…Further, many studies aimed at characterizing the working promoted catalyst (CoMoS) during the HDS process. Among the proposed models, the most accepted by the scientific community is now the Topsøe's model, which was refined by a lot of characterization techniques [60][61][62][63][64][65][66][67][68][69][70][71][72].…”

Section: Introductionmentioning

confidence: 99%

Description of coordinatively unsaturated sites regeneration over MoS2-based HDS catalysts using 35S experiments combined with computer simulations

Dumeignil

Paul²,

Veilly³

et al. 2005

Applied Catalysis A: General

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Section: Introductionmentioning

confidence: 99%

Description of coordinatively unsaturated sites regeneration over MoS2-based HDS catalysts using 35S experiments combined with computer simulations

Dumeignil

Paul²,

Veilly³

et al. 2005

Applied Catalysis A: General

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“…In-situ XAS is ideally suited to probing the local structural chemistry of these catalysts [9,10]. However, in an industrial catalyst the situation is more complex due to a typical catalyst formulation comprising multiple support phases, which give rise to a distribution of Ni-and W-containing phases in the catalyst.…”

Section: Ni-w Hydrocracking Catalystsmentioning

confidence: 99%

In Situ X-ray Absorption Fine Structure (XAFS) Applied to Catalyst Characterization at UOP: Examples and Perspectives

Bare

Kelly

Mickelson

2011

Synchrotron Radiation News

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A commercial catalyst has to be able to perform multiple functions, including: (i) enable the catalytic chemistry via an active site(s); (ii) allow the feed to reach the active site, and the products to diffuse out; (iii) be able to be manufactured on a cost-effective basis; and (iv) be able to be handled for transportation and loading/unloading into the commercial reactor. Thus, the successful development, manufacture, and deployment of a catalyst involve a range of different attributes that relate back to the physical structure of the formed catalyst. It is clear that the development of an improved catalyst for an existing industrial process, or of a catalyst for a process still being developed, is greatly aided by a complete understanding of the structure of the catalyst. This knowledge of the structure is needed over many different length scales from the atomic-level chemical and geometric information of the active site to the macroscopic properties of the formed catalyst. Moreover, knowledge of the structure under reaction conditions, i.e. in situ, adds additional understanding as it is often the case that the actual catalytic site is only formed, or is only stable, under reaction conditions.While there are many synchrotron-based methods applicable for studying catalyst structure, this article will focus on the application of synchrotron-based X-ray absorption spectroscopy (XAS) in an industrial research program, with a series of specific examples from our work. These examples will highlight some of the particular needs of conducting this type of research in an industrial environment. The article will end with a focus on some of the challenges and barriers of performing industrial research at a synchrotron in the US.Researchers at UOP recognized the potential impact of synchrotron-based methods to characterize catalysts soon after the advent of the modern age of synchrotron radiation science. Indeed, in the early 1980s UOP was one of the first industrial users of CHESS at Cornell University, and the first internal report using extended X-ray absorption fine structure (EXAFS) on the structure of Pt/Rh automotive catalysts was written in 1983. In the mid-to late-1980s, UOP became a charter member of the X18B EXAFS participating research team (PRT) at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (and UOP is still a user of this beamline!). In 1993, UOP signed a memorandum of understanding with UNICAT to become a collaborative access team (CAT) member at the Advanced Photon Source (APS) at Argonne National Laboratory and helped develop the premier spectroscopy beamline on a bending magnet beamline at the APS. In 2005, UOP became a charter member of the Synchrotron Catalysis Consortium at the NSLS, and in 2008 UOP became a CAT member at MR-CAT (replacing its membership of UNICAT, which ceased to be operated as a CAT) at the APS, and actively participates in both of these collaborations. In tandem with these activities, UOP has also participated in, and continues to participate in...

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“…NiMo/Al 2 O 3 catalysts used in the present study was prepared by a stepwise impregnation method using (NH 4 ) 6 support (Nippon Ketjen Co. LTD, pore volume = 0.78 cm 3 g -1 , specific surface area = 333 m 2 g -1 , particle size = 150-250 9 10 -6 m) followed by drying and calcination. The thus obtained Mo/Al 2 O 3 catalyst was then impregnated with aqueous Ni(NO 3 ) 2 Á6H 2 O solution followed by drying and calcination.…”

Section: Catalyst Preparationmentioning

confidence: 99%

“…To understand the role of the Co and Ni promoters, extensive studies have been undertaken by using variety of experimental techniques [1][2][3][4][5][6]. Among them, in situ IR spectroscopy combined with adsorption of surface probe molecules such as CO and NO is a powerful tool for investigating adsorption properties of nm-sized sulfide clusters.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Surface Site of Ni Species on NiMo/Al2O3 Hydrodesulfurization Catalyst Sulfided at High-Pressure by Means of DRIFTS Combined With Low-Temperature NO Adsorption

et al. 2010

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A high-pressure DRIFT chamber for low temperature NO adsorption was newly constructed, and used to probe surface sites of the Ni-Mo-S phase on NiMo/Al 2 O 3 catalysts sulfided at high-pressure (1.1 MPa, 673 K). A sharp IR band was evolved at 1,765 cm -1 after NO adsorption at 186-199 K, whereas this band was not observed after NO adsorption at ambient temperature. The band at 1,765 cm -1 was observed neither in the spectra of Mo/Al 2 O 3 , Ni/Al 2 O 3 nor their physical mixture even after NO adsorption at 186-199 K, suggesting that this band results from adsorption of nitrosyl species on the Ni-Mo-S phase.

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An EXAFS Study on the Ni and W Environment in Carbon-Supported, Sulfided W and Ni-W Catalysts

Cited by 70 publications

References 0 publications

Description of coordinatively unsaturated sites regeneration over MoS2-based HDS catalysts using 35S experiments combined with computer simulations

Description of coordinatively unsaturated sites regeneration over MoS2-based HDS catalysts using 35S experiments combined with computer simulations

In Situ X-ray Absorption Fine Structure (XAFS) Applied to Catalyst Characterization at UOP: Examples and Perspectives

Investigation of Surface Site of Ni Species on NiMo/Al2O3 Hydrodesulfurization Catalyst Sulfided at High-Pressure by Means of DRIFTS Combined With Low-Temperature NO Adsorption

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