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The nature of the sulfur tolerance of amorphous silica-alumina supported NiMo(W) sulfide and Pt hydrogenation catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
41269 45883 2012 9 PDF Available
Title
The nature of the sulfur tolerance of amorphous silica-alumina supported NiMo(W) sulfide and Pt hydrogenation catalysts
Abstract

Amorphous silica-aluminas (ASA) based NiMo and NiW sulfide and Pt hydrogenation catalysts were prepared and compared in toluene hydrogenation in the presence of H2S to alumina- and silica-supported reference catalysts with the aim to elucidate the influence of (strong) Brønsted acidity of the support on the sulfur tolerance. Despite precautions to prepare NiMo sulfide catalysts with equal morphology, the stacking degree of the MoS2 phase was found to decrease with alumina content of the ASA. Similar but more pronounced differences of the stacking degree were observed among the NiW sulfide catalysts. This variation in the stacking degree had a substantial effect on the catalytic activity of dibenzothiophene hydrodesulfurization. ASA-based catalysts show higher activity and improved sulfur tolerance in toluene hydrogenation compared to their alumina- and silica-based counterparts. However, the sulfur tolerance does not correlate with the number of strong Brønsted acid sites, nor, indeed, with total Brønsted acidity. Instead, it decreases with increasing Al content of the ASA support. The sulfur tolerance of the active metal sulfide phase is related to the electronegativity of the support. That silica itself does not follow this trend is surmised to be due to its lack of Lewis acid sites, necessary for introducing the active phase-support effect.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (57 K)Download as PowerPoint slideHighlights► Sulfur tolerance of NiMo(W)S and Pt in aromatics hydrogenation evaluated. ► Sulfur tolerance does not depend on support Brønsted acidity. ► Sulfur tolerance correlates with support electronegativity. ► Lewis acid Al sites essential to introduce the support electronegativity effect on the active phase.

Keywords
Sulfur tolerance; Hydrogenation; Amorphous silica-alumina; Support effect
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The nature of the sulfur tolerance of amorphous silica-alumina supported NiMo(W) sulfide and Pt hydrogenation catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volumes 411–412, 16 January 2012, Pages 51–59
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
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Full-text PDF Download
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Any Questions? feel free to contact us