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Effect of surface Na+ or K+ ion exchange on hydrodesulfurization performance of MCM-41-supported Ni–W catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
43819 45990 2007 8 PDF Available
Title
Effect of surface Na+ or K+ ion exchange on hydrodesulfurization performance of MCM-41-supported Ni–W catalysts
Abstract

Ni–W hydrodesulfurization (HDS) catalysts supported on MCM-41 synthesized from two different silica sources (sodium silicate hydrate and tetraethylorthosilicate) as well as on Na+ or K+ ion exchanged MCM-41 were prepared. These catalysts were used to investigate the influence of the surface properties of MCM-41 on the performance of HDS catalysts with DBT as the model molecule. The XRD and N2 adsorption results indicated that the MCM-41 prepared from tetraethylorthosilicate (MCM-41(T)) exhibited the best structural properties. The mesostructure of MCM-41 synthesized from sodium silicate (MCM-41(S)) remained after ion exchange with Na2C2O2 and K2C2O2. Both pyridine FT-IR and Hammett indicators showed that only MCM-41(S) possessed some Brönsted and Lewis acid sites. Ni–W/MCM-41(S) showed the highest HDS and hydrogenation activities. The introduction of Na+ and K+ strongly inhibited the hydrogenation activity of Ni–W/MCM-41(S) but enhanced its hydrogenolysis activity. UV–vis and TPR studies indicated that the introduction of Na+ and K+ into MCM-41(S) may lead to the segregation of surface Ni species and may hinder the reducibility of the supported Ni–W oxides. Spillover hydrogen, which is “trapped” by Na+ and K+, may play an important role in the HDS activity and selectivity of Ni–W catalysts.

Graphical abstractThe introduction of Na+ or K+ strongly inhibited the hydrogenation activity and reducibility of Ni–W/MCM-41 but enhanced its hydrogenolysis activity. Spillover hydrogen, which is “trapped” by Na+ and K+, may play an important role in the HDS activity and selectivity of Ni–W catalysts. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
MCM-41; Ni–W; Ion exchange; Hydrodesulfurization; Na+; K+; Dibenzothiophene
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Effect of surface Na+ or K+ ion exchange on hydrodesulfurization performance of MCM-41-supported Ni–W catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 316, Issue 2, 10 January 2007, Pages 134–141
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us